Dom damage won't ever be as good as blasters, though most combos can do respectable damage, and some great damage. It's the same for Corrs, and blasters have the same variety in their sets.
I'd say the fire/rad would probably pull ahead becauese of having 3 AoE attacks plus a nuke, and higher damage, and those rad depbuffs. The dom does get firey embrace, but doesn't have some important attacks (Fireball! Which is often used in ST chains for fire/).
Mind/ will pull ahead in safety. Corrs get some safety, but it can't beat the lockdown of an AoE hold and fear and confuse.
I'd say doms can be a more fun character when played in a blaster style way.
So give them both a try!
PvP, I don't know.
I love doms and corrs. So many people make the mistake of trying to play a dom like a blaster or controller though and its soooooo wrong. Remember most blasters have some decent defences and better HP than doms. BUT a good dominator can lockdown a whole room of foes with the massive aoe controls. Best method is to attack everyone at once! With a corr you have to juggle attacks and buff/debuff only really but many of them get heals like my energy/rad corr specced mostly for offence. Whereas my dominators are slotted for very high amounts of control and have their best attacks highly slotted only.
PvP wise its down to personal taste, I do most of my pvping in teh arena and either can work really well imo more down to personal taste, playstyle and really what you're fighting. Some things my lvl 50 dom can eat for breakfast snap my corr in half, and vice versa some stuff my dom cant handle my corr can smack down. Zonal pvp wise I think my corr has the edge but only due to being a lot closer to being a pvp spec and build. But in a pvp team, my dom is always very popular.
I'd say flip the idea mate - do what appeals to YOU and what you find FUN. Its what I do and I'm working on 50 number 4 right now solely becaause I make fun builds 
Oh and mind/fire and fire/rad both rock but in very different ways and require extremely different playstyles. I've personally tried a ton of dom combos and all play differently. My current 2 are gravity/thorns and mind/fire - with a plant/elec coming in i12. All designed and tailored differently.
I am a sort of new player in CoX and I really like blaster idea of offensive ranged attacker with respectable damage output... problem is - I absolutely despise heroes and heroic deeds, while feel attracted to the dark side, but a bummer - no real blaster equivalent on the red side, so I'll have to improvise.
The two obvious options for me are Dominator and Corruptor - and both are seemingly an underdogs in damage department.
Corruptor has 75% ranged damage mod and attack set as primary, while can buff himself and debuff targets via seconary. Looks not bad as I understand that by using buffs and debuffs he can levitate his damage to respectable levels. However I can't shake this feeling that Corruptors are more of a buffer than attackers, which make me go eww!!
Dominator, on other hand, seems to be less of a damage dealer on a first glance with his 65% ranged mod and some half-[censored] secondary assault sets, but domination seems to be HUGE damage-wise that puts dominator base damage over blaster when active (at least logic says that 65% + 75% of that = 113% damage mod... better than blaster) and there are means to make perma-Dom (expensive, but if it is my main - I will do it eventually) and Fiery Embrace seems quite uber too with ~80% damage buff to fire for whole 30 secs. So I sense some blaster damage potential here.
Now the question is - can Dominator beat Corruptor on damage done at least on single targets? For sake of comparison lets take Mind/Fire dominator vs Fire/Rad corruptor...
Can dom's cause pain in PvP?