As I read it, the 49-way sticks + a GPwiz49 functions identically to a u360 stick (when wired for analog).
No.
The GPwiz49 in analog mode (there's two but basically the same) can send out 7 values per axis. Center, and three values above center and three below. They might be (I'm guessing the numbers): -128, -85, -42, 0, 42, 85, 128 (normal analog), or -128, -64, -32, 0, 32, 64, 128 (progressive analog), but that's still only 7 values per axis. I call this "rough analog".
The u360 in analog mode can send out 256 values per axis. That means -127, -126, -125... all the way to 128. I call this "full analog". (Whether human's hands and precise enough to hit each one is another issue; but 24 to 64 per axis is reasonable.)
This shows or doesn't in different game to different degrees.
For example, Terminator 2 can be played pretty well with a u360. It can't be played with a 49-way stick, as you can hit only 49 spots on the screen; the u360 and original hardware theoretically have 65,536 possible spots, I'm not sure if the game is coded that precisely.
Other games you'll notice very little difference. Road runner, blitz, Escape from the Planet of the Robot Monsters are all probably fine with either.