Both InCD and DirectCD are fairly similar. The latest version of DirectCD, though, has an improved Scandisk repair utility and it works with CD-Rs as well as CD-RWs, while InCD only works with CD-RWs.
Depending on your burner, you may chose one or the other (but not both!). InCD is very compact so is great for archiving (I hate bloatware!) while for DirectCD you need to have the complete EasyCD Creator package as it is not an independent install anymore.
I use the latest DirectCD, 5.10.209h so I can packet write to CD-Rs (more reliable medium than CD-RW) but using it with the Lite-ON 40125S (or 48125W for that matter, hehehe ) it is a slow process at best; burns are actually much faster on CD-RWs. This may be because of the way CD-Rs are formatted, which is verty different to the way CD-RWs are formatted.
BTW, the latest versions of both are compatible with each other. If you formatted a disk with DCD you should be able to write to it using InCD and vice-versa.