The UK episodes on Dave are repeats, but they only really show certain episodes from series 4 (1992) to series 8 (1996).
Most of the US ones on FiveUS are repeats as well, but recently they have been showing unseen episodes which are made up of the extra unused games which were not shown in the original episodes (if that makes sense?).
I like Whose Line, as well, but I have only been watching it (repeats) for the past few years. My faves are Greg, Ryan, Colin and Paul Merton (and Clive, of course - you've got to love Clive).