I don't know anything about TiVo, but one thing to be aware of is memory usage - if they've gone in the same direction as the games console manufacturers, the machine is likely to have much less RAM than you're used to in the average desktop machine.

TCL can be very light on memory requirements, and the TCL core is very easy to modify to be lighter yet; Perl is rather heavier, and recent versions heavier still.

I used TCL for a large application just before I started using perl, many years ago, and one of the first things I did was rip out all the floating-point support to save more memory - that took me less than a day. I wouldn't expect to be able to do that with perl.

Caveat: my experience of TCL is over 10 years old (version 7.3 I think), and may not be relevant to more recent versions.

Hugo