I owned an AP140 with the 4 inch focuser. Yes a lovely scope. I used it for imaging but did look through it. Very pinpoint and sharp stars.
It was certainly a great imaging scope. I used a 4 inch Tak flattener on it which worked fine. I also got the Quad TCC and used that with it too.
I only sold it because my name came up for an RHA. I sold my TEC180FL as well to fund the RHA. I don't regret the sale. The RHA has been my primary imaging scope for the last few years and I intend it to be in the future.
I did pick up an as new 130EDF GT a few weeks ago. Its a lot smaller and lighter. The 140 was reasonably large and solidly built.
I also have a CFF105 F6 FPL55 oiled triplet with 99.4% strehl in green and a 3.2 inch feather touch focuser. Superb, superb.
I plan to have the AP130GT operational shortly. Just waiting on the usual adapters for a new scope. I suspect the 130 will be a match for the 140 as I found the focal length of the 140 a bit odd in that not 100% widefield and not really long enough for longer focal length images.
I prefer a high quality decent aperture to do widefield imaging. Long focal length is best served with CDKs or Newts etc. The TEC180FL is a large scope, handleable though but pretty close to the limit. It needs a decent mount although I managed for a while using a Tak NJP mount but it sometimes did not work too well.