I have been working already for many years with Tk and so far I have not found something that could achieve the things I have done with Tk.
The only things that are not so user friendly about Tk is the placing of the objects using pack. You bassically have to think very carefully upfront where you want to have everything and joggle around with frames to place it at the location you want. (pack versus canvase versus grid).
Also if you use it on a windows system it does not have that very windows native look.