If you like Defiance 2.0, and building up with little attacks before letting loose your good attack, Beam Rifle might be your style. Its usefulness is limited for blasters, though, since we have a habit of dropping enemy HP quickly so that teammates can finish them off faster, and when an enemy's HP bar goes bye bye, any Disintegration on it goes bye bye too.
On the other hand, most blasters I know just Aim-BU and ignore Defiance in the same way that defenders ignore Vigilance. If you're more like that, where you feel the first 5 seconds of a fight are too critical to be putting off your best damage powers, go with Ice. You can go straight into Aim-BU-Rain-Breath with no setup, no screwing around, no worries about certain enemies going down too soon.
Honestly, Ice's AoE is not that bad, in comparison to the AoE wimpy sets we've been getting recently. I think it only has a reputation for low AoE because it's close to but not quite a mirror of the Fire primary, which can Aim-BU-Rain-Breath-FB.
Finally, if you like utility, you will love /Ice.
Beam Rifle isn't necessarily bad, it's just specialized. Beam has great single target damage over time but it takes time to ramp up and you have poor every-spawn AoE capability... since most Blasters rely heavily on burst damage and AoEs that can be bad. If you want to dish out maximum damage to bosses, EBs, and AVs then Beam Rifle is going to rock (provided of course that you have a way to stay alive 
)... Ice would be more survivable but I believe Beam does outdamage it against hard targets where you can use Disintegration often. I'm actually considering a Beam/Ice Blaster since /Ice gives enough mitigation to keep a single target Blaster alive... on teams it should play like a squishy, ranged MA Scrapper: pick a boss, make it disappear, repeat.
Cascade, level 50 Blaster (NRG/NRG since before it was cool)
Mechmeister, level 50 Bots / Traps MM
FAR too many non-50 alts to name
[u]Arcs[u]
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I wish I could offer anecdote rather than conjecture but my beamer is still pretty low level. That said, it seems like with judicious target selection beam should have aoe at least as good as ice. Not equally consistent aoe, mind, but while the lows are a bit lower the highs are a lot higher.
Between their cones beam's is easily my favorite. Shorter animation, much shorter recharge and longer range are all awfully nice. It does do less damage, with a footnote that reads simply "disintegrate."
It's difficult to directly compare the rest of the powers but a moderate damage rain plus a devastating but endurance crashing rain do not add up to more than a slow recharging crashless nuke, a three target "cone snipe," and the shiny new spreading toy in my opinion.
As for disintegrate specifically, it isn't that big of a challenge to start a fight by targeting a boss or lieutenant and if you do that you can be fairly confident you'll get four or five tier 1 or tier 2 attacks off on them. In a medium to large sized spawn, each of those attacks should spit out a couple disintegrate spreads. Sometimes less, sometimes more. Lasting ten seconds a pop, as soon as you have a comfortable numbers just drop the cone and do very solid aoe damage.
The obvious issue is your team killing your dudes before this process can play out. Even in that case you're still doing good single target damage and average aoe with a dash of explosive armageddon whenever overcharge is up. As soon as team steamroller hits a snag, disintegrate's effect will naturally express itself more and contribute more aoe. Content where you face large groups of sturdy foes also plays to your strengths.
Thank you for your advice. I feel a little better about beam rifle. I'm still not sure what I want to do yet, but I might give it a try.
Beam Rifle is great for it's speed of activation. Damage-wise it's as good as any powerset. Focus on what you want to RP as is probably the best advice since both Ice and Beam Rifle offer very good gameplay.
Quixotik
"I did not say this. I am not here." -Guild Navigator
With the two combos you pointed out, there really won't be much of a difference. Your ice/ice character will probably open up with a hold or two, maybe an immobilization, and then go to town with mostly ST blasts. Your Beam Rifle/Devices character will probably open up with Trip Mines, Smoke Grenade, and Caltrops, and then go to town with mostly ST blasts.
I can vouch for Ice/Ice being a beast, and a very survivable one at that. My main and favorite character is Ice/Ice. Beam Rifle seems like it will also be a damage dealing beast (you really don't even need Disintegrate except on Bosses+), and Devices will offer a decent measure of protection as long as you slot it well (Slow in Caltrops, -To Hit in Smoke Grenade).
@Winter. Because I'm Winter. Period.
I am a blaster first, and an alt-oholic second.
I'm finding Beam's singletarget is brutal fun. Mine's running on a Defender, but to restate what others have said, Bosses drop really fast. Outside of Sonics, I don't think I can remember a Defender who chewed through hard targets as fast as my Beam does.
You're never gonna be great at spawn sweeping unless you can really ramp your nuke's recharge quotient, but I'm envisioning the day when my Time/Beam is Defense capped and soloing small groups of +4s. And a lot of that is due to Beam's takedown.
"I'm flying free with my beautiful butterfly wings!" ~ Randy Marsh
These powersets are very similar in that they both focus on single target damage, and I've heard nothing but bad things about beam rifle. My question is whether beam is currently better than ice, or if ice is better all around.
I know that ice offers a lot of control and utility, beam rifle does not appear to offer much in the way of that. I am well aware that ice has more control and very likely more utility, but does it do more damage as well? Does beam rifle offer more AOE damage? These are the kind of things I am curious about.
If it matters, I will be going ice/ice or beam/devices. I have specific character concepts and builds up already for both. So feel free to compare /ice to /devices as well.
Does beam have any redeeming value for blasters or is it really as bad as they say? I know it's still a bit early to be asking these kinds of questions, but I like the beam rifle a lot. I simply don't want to play a broken/terrible powerset, and regret it at higher levels. I don't hate ice though or anything -- I'm perfectly fine with continuing to play with that instead.