The only problem I have encountered with InCD occurs when if is necessary to change the physical CD-RW drive - then InCD will not run. To get around this, uninstall In-CD, install the new driver and then re-install In-CD.
I find it very useful for writing bits and pieces to CD-RW - as its blurb goes, it will make a CD-RW like a large floppy.
More problems will arise from the use of CD-RW than from In-CD due to their unreliability. If you have an important file, burn it to a cd-r - nero will allow multisession cd-r burning and the disks are pretty cheap nowadays.