I've owned two of the 150mm f5 Omni's since 2015, the first was used and the second new.
I sold the first due to a grossly overcorrected lens, I did respace the lens and improved its correction somewhat. The second was better corrected, and I still own it but I'm struggling with the focuser. I've been through several focuser change outs on this scope, however the images are actually usable up to about 120x with filtering. In general you'll use less than magnification anyway for most deep-sky observing. One feature I do like: the tube is fairly well balanced and easy to mount on CG5-class mounts, it's very compact given 6" aperture.
I've seen more color in nebula and stars using these scopes than others I own (including larger reflectors) of course you might suspect false color is the cause. M42 revealed a beautiful red-green coloration several winters ago. Last summer I also experimented with planetary imaging, using dense color filters, see attached photo of Jupiter. While seeing in this case was worse than average, you can see some potential.
I could not agree more. I owned a reflector....1100 Edge HD and since getting an ES 102 mm APO, I don't regret selling my reflector.