Yeah, there is a reason PG chose PLT Scheme. To begin with, coming back to arc will not be difficult. PLT Scheme has a lot of libraries and code samples. And it's mature and portable. The dialect is still actively being used and developed. All good reasons to use it.
Personally I've finished my website in arc, I just need to do one more move to the production web server. I'm going to leave it in arc and update it as the language is updated by PG / Community.
I think anyone looking for another language should consider common lisp and smalltalk. I've been coding in both recently and it's been a pleasure after I familiarized myself (again).
