Wow, I used to check this thread every day or so but stopped during the summer because there were no new posts since May. All of a sudden in October they started popping up. Amazing the Neo550 is still kicking. Anyway, I've been using mine since 2010 and have over 600 title's on the movie wall (BR & DVD ISO). I love the 550 and bought a "backup" unit a few months ago just in case mine shoots craps.
Tagging still seems to be a hot topic so I'll throw out my experience. It probably won't help anyone this late in the game but you never know. When I started to look for a tagging solution I was frustrated by the taggers at the time (they are a little better now). Difficulty in finding exact movie title matches, missing info, and poorly written overviews etc. I was using DVD Profiler before as my "library" before the NEO which was great (easy to download movie info, great reports, easy to change overviews, cover art, free, etc.). I hated the thought of looking up all that same info again - and then having to edit half of it again. Fortunately Profiler had an export function for all the movie info but the cover art.
I wrote a program (Visual Basic) that takes the XML output file of DVD Profiler and creates Neo-compliant TAGS from it. If you drop a screen shot of the cover art per movie into the XLM folder, the program will re-size it and include it in the TAG. It will do up to 100 movies in a minute or so it made pretty quick work of the 600+ & got the Wall up pretty quickly. Of course it took forever to decode the TAG file format & get the program working (it's a weird one).
My next issue was the occasional home movie, YouTube, TV episode, or occasional minor edit / revamp etc. that wasn't in DVD Profiler (and/or I just didn't want to mess with Profiler). I wrote another VB program that will edit or create one TAG at a time. You can also add/change cover art you supply. It is strictly MANUAL and does not look up any information online. Still, it's great for quick changes and creating tags you all ready know the basic information for. One advantage is for creating TAGS that basically contain the same actors, genre, cover art with different titles & overviews. Create the first one, change what's different, and save it with a different name.
Anyway, this is probably too long a post for something no one's probably interested in - so I'll wrap it up. If anyone is interested in a DVD Profiler To Tag Creator or a simple manual Tag Editor / Creator, drop me PM. If you have questions that may be of interest to others just post the questions here.