I was just out today with my Lunt LS50 on a Celestron AVX mount taking some images of the sun (see the results here on CN). I also use the AVX with my 80mm Stellarvue (for lunar and DSO imaging) and the mount is fine for those kinds of tasks (particularly planetary and lunar/solar). In fact, the AVX is what I typically use with my Celestron C6 to do planetary work (see animation of the transit of Mercury using the AVX).
That said, I don't often try to use the AVX for long exposure or narrow band work on DSOs. The latter can be done at certain image scales (short camera lenses) but don't expect to do high-resolution, long-exposure, narrow-band imaging of DSOs on the AVX without suffering some grief an/or compromises.