Well that's because yeah, they pretty much all suck. Mostly because DLNA just sucks big time. Those developers can't fix a poor technology "standard" so it's not really their fault. I've been down that road before with my PS3. I've tried the same 3 you just mentioned as well as a few more. PS3Media Server was the best of the bunch but it still wasn't nearly satisfying enough to make it a full time media solution. I would always prefer just playing the media straight from the disk because there were so many problems with it.
Especially because the fast forwarding and rewinding capabilities of any DLNA solution was almost always atrocious and you often get kicked out of a video when attempting to use playback controls or even just playing files that are supposed to work. And the UI is horrendous with very little to no metadata support and the little support it has takes too much manual work. And like you mentioned in your experiences, the video and audio were often out of sync and other issues as well.
The ATV2 resolved all my problems and now I only use the PS3 for Blu Rays and games which it is excellent at. I'm sorry but depending on your standards you probably aren't going to be too high with any of those types of solutions with the PS3 except for maybe using it every now and then in a pinch. The ATV2 preset in the Handbrake nightly builds along with the ATV2 makes for some beautiful HD encodes and a very nice playback experience. I highly recommend it.