You inspired me to have a play with my Celestron Omni 150 f5 tonight, and I thought you might like some comments. (I have had it for a while, but haven't had much opportunuity to put it through its paces.)
I bought mine (used) to use mainly as an outreach scope (the punters love a "real" looking telescope!), but like you I had been looking for one for quite a while (who doesn't want a 6" refractor!). I have a Tak TSA102, so I am quite used to near-perfect views; but even so I have been impressed with the Omni. Yes it has CA, but not as much as I feared. On bright objects like the Moon it is hard to get the focus just right because the red and blue are at different points; but like the referenced review I find that a Baader "Fringe Killer" filter helps to get a sharp focus, even if it does turn the Moon yellow... I don't generally use the filter with DSO's though. (I would like to have a try with the "Contrast Booster" filter as Marksabb mentioned above, but I don't have one...)
Looking at M42 tonight I was impressed by how much nebulosity I could see, even though the Moon was not that far away (sitting in the Hyades as I write), and I am looking through a suburban sky. At 100x (with a Tak LE 7.5 eyepiece) the "wings" of the main nebula filled the field, with M43 clearly visible with direct vision. What amazed me though was that not only was the Trapezium clear and sharp, but I could also make out the E and F stars. These were even more apparent at 125x. The seeing was a bit wobbly, but I increased the power to 250x and the stars remained pretty much "textbook" for an achromat.
I swung around to Eta Carina just for fun (I am at 35 degrees South). The "Keyhole" was nicely visible, and again from 100x I could make out the double-lobed shape of the "homunculus" around Eta. This was clearly a red colour: this is the first time I have really noticed this colour, and I have looked at this through a 24" dob...
Down to the "Jewel Box", and again the view was excellent, with sharp stars and lots of colour.
No planets just at the moment, but I think it will do surprisingly well when Jupiter and Saturn again appear at civilised hours. It can cope with 250x on a good night, as it did tonight even though the seeing wasn't good!
This scope is a keeper, and I am looking forward to taking it to a dark sky in 6 weeks or so to run it against my 12" dob on some DSO's.
Good luck with yours when it arrives. Make sure you post a "first light" report!
All the best,
(PS: I was using a home-made alt-az mount tonight, but it sits quite happily on my Stellarvue M2, and tracks happily on my early model iOptron Mini Tower.)
Edited by DeanD, 13 March 2019 - 06:44 AM.