He was meh in Generations because for both Sonics, your Rings depleted REALLY quickly. And there weren't enough Rings in the stages to make up for this.
And Classic Super Sonic was basically just an invincibility power-up. You didn't move faster. In fact, I could swear his acceleration was slower.
Modern Super Sonic was also invincible, but his added perk was that he had infinite boost. And most of the time, the boost button didn't make him actually boost. Instead, he would start flying along a spline path, skipping sections of the level, and making his Rings deplete at an extreme rate (you could go from 200 to 0 in a matter of seconds). It was a cool thrill the first time, but when you see it once, you never need to go back (plus it could lead to death if you ran out of Rings while flying over a bottomless pit). Modders have fixed both Super Sonics on PC, though.
In Lost World (Wii U) however, he's invincible, he's faster, the Spin Dash is replaced by a boost that is even faster (which also means no need to charge the Spin Dash unless you're using parkour moves), he attracts Rings as if he had an electric shield, and he defies the games normal physics when using parkour. Plus, levels are bursting with Rings, and with that added Ring magnet Super Sonic has, it is literally impossible to run out of Rings. He can also use Wisps, unlike in Sonic Colours, but you revert to normal Sonic once you use one (but provided you still have over 50 Rings, you can just switch right back to Super Sonic when the Wisp finishes).