It is a good idea to disable nero incd anyway unless you actually use it. If I recall right, the versions of incd that came with 5.? were even worse about taking over control of the drive. Havind diffrent burning softwares on your computer usally won't cause problems. I have had several on the same computer at the same time before. You just have to worry about packet writing software like incd because they can caused problems reguardless of if thier are other programs. I wouldn't even worry about it unless you install both and thier are problems. If you have problems, just run the nero clean tool and it will wipe out everything that nero installed.
I also agree with others, consider the new version of nero. I have roxio somewhere (cannot remember if it came with a drive or if I bought it) and I was not really impressed. The new versions of nero is a full, high power burning suite comprized of many programs. It is not nessasarilly the best program for everything, but you will not find another single program that can do almost everything as well as nero does. You can find oem versions online really cheap (they were intended to be sold with a drive or a computer etc.), so they may be limited versions and may not work with all hardware. If you watch the major stores I have seen it several times cheap after rebates (as cheap as 10$ for the full retail package). I would at least download the free trial and see how you like it. I also sugest you check out anydvd (it has a free trial too).