You would want to use SPRecovery if you don't want to use Clockwork as your recovery program. I don't like using Clockwork or rom manager myself, so I stick to SP. If you make an advanced nandroid backup before you go screwing around with flashing different kernels and roms, you can simply boot into recovery after something goes wrong and flash back to a previous stable version. Same thing as Clockwork really, but with SP, you can just flash roms by naming them to "update.zip" (and also flash a bunch of other crap like baseband updates, themes, etc. the same way) and running them from the root of the SD card. If you were using rom manager and Clockwork, you would simply boot recovery in a similar manner, but rom manager just isn't for me, so I stick with SP.
Yeah, have sp recovery flashed, then boot into it with power and X...holding X, then chose backup, then choose all asterisks, then choose advanced nandroid backup, then name it, then press enter, then perform back up! Check my sig for further details bro. It is a simple, but needs to be explained process! Good luck!