The routers at Langley Airforce Base in Virginia are fun to mess with.....ummm.....I mean I would think they are....yeah that's it....lol
But on a serious note, I just use whatever I can get my hands on...usually a friend's network or something b/c like I said elsewhere....I'm cheap lol. But since all routers usually operate the same way, I would probably just get the cheapest one I could find from a pawn shop or something to play around with. I haven't looked at the one you mentioned but I will check it out, I need to set up a dedicated lab here soon for playing with and learning the metasploit framework.