First, I have a VMC110L, so this isn't about what I've heard or think it may be. Second, I'm a visual observer, so I can't really comment on any imaging efforts.
I bought this scope with the notion that it was small, but had around a 4" aperture, which were features for which I was looking. It was also relatively inexpensive. Nothing is free, however, and assumed that there was a potential for some corners being cut somewhere. So I was going into this more as a grand experiment (well not that grand, but I thought it would fun).
The overall build quality of the tube is good. It is all metal with a very well done fit and finish. The diagonal and spider is all metal, as well (the flat black color and its shape makes it look like it is possibly plastic, but it is not). It has two attachment points for the included dovetail bar, one on the side and one on the bottom, so you can easily attach it to a conventional mount or certain side mounts (such as the Vixen Porta II, what a coincidence) and maintain its orientation. There are two control knobs on the back, the focus knob and the flip mirror knob. They are both mechanically sound, the focuser having a nice smooth action with just enough resistance that you can tell it is working (this is really an important thing to understand, especially when you are in the dark). There wasn't any slop in my focuser, in other words, when I changed direction of focus it changed immediately without any detectable take-up (this was confirmed in actual optical use). The flip mirror control works well with what feels like a cam controlled positive click in both mirror positions.
Sometimes I hear comments about clean lines and it isn't always clear what that means. Outward appearances are a nice aesthetic, but that does not always add to function. Well, in this case, the VMC110L has very clean lines, which makes it an easy form factor for packing, so its appearance does add to the function.
So, generally the build, fit, and finish are pretty good, and if you could base the value of the telescope on those aspects alone, then the price charged is actually a very good deal indeed. But this is a telescope and ultimately the optics are what really counts. Related to the optics are the mechanics, the stuff that lets you adjust the optics.
The short story, the straight through optics are quite good, but the built in flip diagonal mirror is a major weak point that compromises an otherwise fairly decent optical system. Additionally, the collimation adjustment screws are there, but they are compromised by the fact they are glued in place. The focuser is indeed smooth and responsive, but there is a slight mirror shift when you change focusing directions. I will take each of these separately.
The main problem with the flip diagonal is that it isn't collimated, nor is it easily adjustable. Because of its misalignment, you cannot collimate the scope through the flip mirror. However, the straight through collimation (with the mirror up out of the optical path) was actually quite good in the model as it came (checking with a Cheshire and an autocollimator and then later with a star test). So I put a diagonal on the back and use it only in the straight through configuration. But I still wanted to have the ability to fine tune my collimation.
The collimation screws are push/pull pairs in 3 spots found in the back of the OTA. Two pair are behind fitted rubber gaskets and the third pair is behind the flip control knob, which is actually pretty easy to remove. The screws are glued, are deep in a well in the back of the scope, and they are Phillips head aluminum, so don't try to force them loose or you will strip the heads and have a more difficult situation to fix. In my case, I poured a few drops of 91% alcohol into each of the wells and let them soak for a while. Then I used the best fitting Phillips head screwdriver I had and began to gently rock each screw until it broke loose. If you go to the Vixen Optics USA web site, the US distributor for Vixen, you can download an augmented instruction manual (not the standard one provided from Vixen) for the VMC110L that describes all of this with some pretty good pictures showing the collimation points and how to make adjustments using the push/pull screws.
If you want to replace the screws with something less easily strippable, made of stainless, you will be looking for #4-48 screws, which are not standard at your box hardware stores (you will find #4-40 if you find anything in a #4 size, and they won't work at all). Likely, you will have to order these online unless you have a specialty hardware source that stocks these (fortunately, San Antonio is a nearby city for me and one of the manufacturers of these screws is there).
The collimation can be fine tuned quite well and if you are willing to work with the adjustments, you can actually make this telescope sing well optically. Before I tweaked the collimation, Saturn view started to degrade at around 150x. After tweaking, I was able to take the magnification up to 172-207x pretty comfortably. It seems to hold the collimation well, also. So if you willing to invest a bit of time, you can have an instrument that will yield some very nice views.
A couple of additional notes - There has been some talk about the larger central obstruction and thicker curved spider vanes causing a degradation of potential contrast (a lot of these posts on various boards have been from non-owners, by the way, though I have seen that comment from at least one person who owned one). When properly collimated and using a good quality eyepiece, this instrument yields a very nicely contrasted image (with no spikes, which means the spider design works, of course). I suspect that a lot of perceived contrast degradation came from collimation problems more than actual contrast reduction from the secondary and spider.
As many owners of this scope have mentioned, the cap for the scope is a bit of a tight fit, but I really haven't had any problems with it.
Also, the supplied single reflex finder is mechanically a piece of junk in my opinion. It is simply a poor design that looks a bit cobbled and it does not hold its adjustment well. The switching mechanism also failed early on in its life (after I had already decided to replace it with something better). A reflex finder is all you really need with this scope, so just find a good dot finder that uses a finder dovetail and you will be in great shape.
So, in summary, overall this is a good scope for the price (at least in my opinion), and if you are willing to spend a little bit of time on its adjustments, you can make this a great portable scope for lunar/planetary work and some of the brighter DSO's. It is a very packable design and the optics, when tuned properly, are very good. However, I would not count on using the built-in diagonal and you will need to replace the finder. So you will still be out the additional cost of a good quality 1.25" diagonal and a reflex finder. I am really enjoying this scope and it is a great grab and go instrument, but if you are looking for something that is a bit more turn-key there are other options to consider.