You like the roll-under with nD6 (where n goes up as difficulty goes up) mechanic? I prefer Mongoose's standard roll 8+ with 2D6 to succeed for everything. Less fiddling with DM calculations and dice adding, and focusing more on role-play.
Ayup, I like T5's nD6 where n goes up with difficulty. It goes up in a standard way with nice words just like MgT.
And I've never had any reason to dislike roll-under, though some people seem to have big problems with it.
I've found T5's task system is strong enough to support anything I throw at it.
Now, I'm not sure I like a single reference book that is 650 pages. I'll probably be using the PDF version and only using the working copy of the book to show other players. That's why I got four books: one to give a friend for a late Christmas present, one for a working copy (w/ bookmarks/tabs), one for a reading copy (only me), and one to sit on the shelf to stay there until one of the other books break down.
I will admit that 650 pages sounds like a lot, but it's got a lot of stuff in it, including many things that were formerly in supplements.
One thing I would pay for, though, that seems to have been left out, is a shopping catalog with a lot of flavor text, or even a decent shopping catalog so that I don't have to use the Makers. I've got the starship building process down, but I am hoping that somebody writes a good WeaponMaker program.