I too had a 748 (99 mono) and it's really hard to compare it to an R1, they are in two completly different playing fields. If your addicted to the power of the one, you'll be disapointed with the duc. To me the duc took more effort to get it to turn in, felt more stable, and gave more feedback, but then again this will depend greatly on how you have your suspension and chassis set up. The 748's sound nice with their extra bit of rpm range over the bigger duc's, especially with a nice exhaust system ( I had a Forza which I was really happy with). With a full system and a chip they will easly power wheelie first gear, just don't expect any more. As stated earlier in this thred, maintainence is another issue that deffinetly needs to be considered, there will be more with the duc. I did love my duc though, and will deffinetly own another. I would need more motivation than the 748 though (just not the 999, ugh!).
..oh yeah, and they had the Marelli injection in 98 (as with all the other years if I'm not mistaken, could be wrong though).