The nicads will be fine! Size for size, they're actually capable of supplying more amperage than the NiMh.

When I got back in after being gone for a long time I ask the same question. It was suggested I go NiMh, so I did! My newest nicads were over 10 years old at the time, and though many would still cycle, I didn't trust them on some of the stuff I was flying. I repowered everything with NiMh (4 planes and 2 transmitters). Won't go into all the details, but the short story is I'm not happy with them.

Go with what you know for now, just don't go overboard like I did. When you get time, look into A123 or LiFE. They're the same technology, are awesome, but everything you know about the care and feeding of nicads aren't going to do you much good. You'll need to take some time to come up to speed with this new stuff. When you do, pretty sure you'll like them. -Al