welcome to the forums man,
first off, congrats with your Ibanez, its a big step up from a shitty squier.
secondly, if you want to know what amp fits your needs, you gotta ask yourself some questions, how many watts do you need, are you considering to join a band and what kind of sound do you want.
I'de say, you want a metal sound, right?
Peavey Bandits are good amps for their money, and they pack a punch, but there's way more brands out there. I'm not too fond of the lower line Marshalls, the non-tube one's aren't that good in my opinion. (mind you I'm not talking about TSL's or anything here)
it kinda depends on what ammount of money you have to spend and what you're going to use the amp for, if you're going to do some rehearsal with a drummer and bassist, you'll need around 100w (non-tube that is) and some descent speakers in your amp. (like celestions etc.)
Okay, now to the amps you selected, the Randall RG100SC looks nice, 2x12 celestions, 100w, reverb, chorus. I haven't played this amp myself, but I bet it sounds pretty powerfull (Randall has kickass sound in most of their amps)
The Marshall MG250DFX has some good features too, pretty similair to the Randall but with digital (crappy) effects added, seriously, I don't like build in fx at all, especially not the Marshall one's. It's just my opinion, but I think you're paying too much for extra fx which suck and you probably won't use that much.
here's a link to the Peavey Bandit 12'
Peavey Bandit 112
and here's a link to the Peavey Special 2x12'
Peavey Special 212
both these amps are good value for their money, I played the Bandit, and it's one hell of a good amp for its money, the Special is even better. and they're both relatively cheap for what you get.
Ofcourse there's WAY more amp brands out there checking out, but it kinda depends on your budget.