Below is an excerpt from Wikipedia, which should answer most of your questions.

"A single-chip solution, the Banshee was a combination of a 2D video card and partial (only one texture mapping unit) Voodoo2 3D hardware. Due to the missing second TMU, in 3D scenes which used multiple textures per polygon, the Voodoo2 was significantly faster. However, in scenes dominated by single-textured polygons, the Banshee could match or exceed the Voodoo2 due to its higher clock speed and resulting greater pixel fillrate."

I own both a Voodoo2 & a Banshee card. I recall that there were some issues with the Banshee on some games (Need for Speed 3 comes to mind) but, patches were quickly released to address these issues.
There are some sites where you can download all kinds of patches and drivers.

From the games I played back then, I never picked up any issues with my Voodoo Banshee.

The benefit of the Banshee over the Voodoo2 is that it has the 2D component build in as well (no need for another 2D card in your system). However, due to the performance hit in scenes with multiple textures per polygon, you might want to consider a Voodoo3 instead (it's available in both PCI & AGP configurations).