I have bought both the original Revolution styles and sounds couple of years ago and just few days ago my wife surprised me with an early Valentine's Day gift and got me the new PLUS pack.
First, I would say the ONLY thing negative about these is that they are expensive AND limited to certain genres (Latin, Pop, R&B, Funk, etc.). However, I understand that to produce something on this level probably took MANY hours of labor and, as someone pointed out, if you divide the total cost per style it comes to about $10/style which is a bargain. Unlike some other offerings, every style is very complete (including intros and endings) and there are no "B" grade styles.
The styles are very "European" or "Italian." And I do mean it as a compliment. If you like how KORG arranges its styles, you will love these. Yamaha styles are often very busy, you need to turn off parts and they may fatigue you after a while with some of the "ear candy." Here, the A-B-C-D variations build up and get more energetic as you would expect but the changes are more subtle, gradual. The extra parts that come in as the styles build up (e.g. strings, horns, etc.) are very tasteful.
I believe the styles are combination of live recordings and programming. The bass lines, for instance, I know they are recorded live and so some of the guitars. The end result is extremely musical, life-like and there is a definite "groove" you feel which is often absent from MIDI styles. That is what I think the algorithm does. It "rotates" the live parts so that the result is feeling a live musician is playing with you.
I am an original Tyros 2 user and I have been through the progression of 2-4-5 and now the Genos. I believe that the Genos is so advanced sonically that if/when V2 comes out it will be an incremental update perhaps focusing on the UI vs advancing the sound. It has been now 4 years since I got the Genos and it still sounds fresh.
The key thing for me with not upgrading is having new/fresh styles so I keep being interested in the instrument. With spending few hundred bucks on bunch of new styles that sound AMAZING make me feel like I got a new keyboard for a fraction of price and I will probably keep this strategy coming as long as Sample Creator keeps making new styles.