i perfer tamagotchi's 'cause you can take them with you and you can get differnt tam characters.. but if you get those neo-pet game thingers (i have 4 ) you can also take neo pets with you but you have to stick with the same thing over and over and over again.and tams are smaller.
Personally I'm in the middle, though Neopets is a MASSIVE site with many many things to do, it's not portable, thats my ups for the tama, it's easy to access and it's more like a real pet