your going to get a slew of different opinions but their just that-opinions. My opinion, and it's just an opinion, that resistance trainers are more aimed toward a person wanting to get as much of a workout as possible, whereas rollers are more for balance and more of a road feel. Trainers are more stable, you don't have to worry about balance or coming off a roller, and you can easily stand and sprint with a trainer. With a trainer you can also keep training after an accident where you may have had a shoulder or arm injury.
Trainers though do nothing for working on balance, but you shouldn't have to that anyways; you wear out the rear tire fast but you can buy special rear tires made just for a trainer but you can't use it on the street which means you would have to change the tire or wheel before riding on the street or trainer; also you can break or damage skewers which is why most trainers supply you with a cheap steel skewer to use in place of your good one.
Rollers I have covered their pros, more realistic road feel, better shifting ability, help with balance, help with pedal stroke because if your stroke is bad or choppy you will fall off the roller!
Rollers cons is that most have no resistance, but some real expensive ones do.
Which one do I like? I like the resistance trainer because pedal stroke and balance is not an issue for me, and the cost is way cheaper then going with a roller with resistance. But others will tell you they like rollers better and that's ok. You decide from the suggestions which appeals to you the most and go with that.
Keep in mind all indoor training devices are BORING! You need to have water at hand, and a fan blowing directly in front of you to simulate being outdoors where the air current of you moving forward keeps you body cooler. A TV is helpful, and there's even training videos you can pop into a tv and follow the program.
