Debugging is really hard.
I've never found this to be a big problem. You can either attach a debugger and walk through, or stick a load of println/logs into the code to work out whats going on.
Logging is frankly awful.
I agree the stack traces generally provide 4 pages of useless info, with the occasional line thats informative. However its a small price to pay for such an awesome framework.
The STS Eclipse IDE is of marginal value.
Eclipse has piss poor support for Grails. Use IntelliJ if feasably possible. I am a tightwad, but if my company allowed me I would gladly pay the cash for IntelliJ.
