It is a good amp for the money. My dad runs one with the 1098 pro through Kef model fours/200c centre & it sounds great with movies/multi-channel music dvd`s. It`s competent but not great in two channel stereo.
using a splitter cable would be fine and I doubt you'd notice any degradation in signal quality as you're not putting anything additional in the path you're merely dividing the signal.
I guess in theory it could give you a slighly higher S/N ratio but it would be so minute it would be hard to measure, let alone hear. You'd also have to run your pre-amp at slightly higher volumes to compensate for the gain reduction (which might offset the S/N increase anyway).
Anyway, the general consensus seems to be that you're better off putting all your money into a single amp rather than two amps at half the price and bi-amping.
I use splitters in exactly the way described. I have 2 x 1075 amps fed from a 1098 processor, bi amping the front 3 channels and using the rest to power the 2 side channels and 2 rears. i tried to get a custom cable made up by Chord to use the DB25 input of the RMB's but gave up on that after chasing them for a few weeks, just trying to get a price on it (they saw no reason why it couldn't be done though). No problems up till now powering the front 3, which are KEF Ci2000s. The only thing being the lack of bottom end from the KEFs and i need better sub integration. Still running my old REL at the moment but looking to move onto something better.