I found it very usefull and flexible, you get tons of options (and belive me you can get lost tweaking trhu a single tone) you can edit the output to studio, combo front, PA, all of this over a tone you allready worked let's say on headphones (this can be tricky but as I said...tweak, tweak, tweak).
Superhuman is right... there are other systems around that might sound better, but for the pricetag... you get plenty of good stuff.
Besides modeling, you get lots of stompboxes, copresor, gate, EQ *(wich makes wonders for your sound), delays, chorus, reverbs, wha pedals, volume pedal (and with an extra expresion pedal sold apart you can have 2 pedal one for volume and other to tweak/wha), considering this as individual pedals you can spent a small fortune and it's all inside the POD.
Over how it's build, is made of metal... not plastic like some other pedalboards.
I love metal, and have some killer patches done in mine, but I laso like to get some mellow round bluesy sounds with some flange or delay or heavy reverb and it works great too, as I said it is really flexible.
Bout making your own tones it's pretty easy and userfriendly, I wish I could have a quick refference bout wich sound emulates wich amp or stompbox but besides that is pretty much intuition.
Like I said... I love my POD, cause I can have some killer tones and stuff to mess around, eventually I would like to get a nice amp to get the tone pure out of it (Mr. Aschleman recomendation) and maybe use it as stomp only stuff but it really is a nice pice or gear to have before you get into more expensive gear.
Power corrupts. Absolute power is kinda neat.