I was a long-time Tcl user and loved it. [incr Tcl], incidentally, is not a play on "+=1", but "++"; i.e., [incr Tcl] is to Tcl as C++ is to C. Speaking of event loops, before Tcl had its own event loop, I wrote a select()-based event loop extension to Tcl that was similar to the Xt event loop. For that, I was (or still am for all I know) listed as an extension contributor in the Tcl/Tk FAQs.

[incr Tcl] was a great OO framework for writing GUIs. Perhaps not the greatest framework since it was trying to mimic C++.

As antirez said, "It's like learning Scheme or FORTH: mind changing."