Even if it does seem a bit rip-off, it's a pretty decent idea. Only for two reasons, though:
1) working when both parties are behind firewalls. There's really no 100% foolproof way around this without using a dedicated man-in-the-middle server.
2) security, both the SSL encryption (which isn't really all that strong, but shows that they prefer taking opensores packages instead of writing their own), but also the "activation code" thingy. Guiding people to download tight/ultravnc, set up settings and security etc... is a pain in the behind.
What makes it come off as cheap is the use of VNC. I don't know how efficient the protocol itself is, but the idea of taking screen screenshots at regular intervals doesn't work too well. Even on a 100mbit LAN, VNC has always seemed pretty laggy to me. Ultr@VNC with GDI mirror driver is an improvement, but I've yet to find something that beats Microsoft RDP...