What levels are they? If you aren't using heavy DO's or SOs, enhancements don't help much. And slug does more damage than shriek anyway. But here is the breakdown:
Ice: Slow effects, smashing/cold damage (lethal?), fairly high end cost.
Fire: Damage over Time, fire damage, area of affect attacks come earlier
Electricity: Endurance drain, energy damage, a utility set with holds and a pet
Energy: Knockback effect, energy/smashing damage, giant energy bolts which send people flying. The coolness.
Assault Rifle: Higher accuracy to compensate for draw time, has some knockback, smashing/lethal damage, no nuke but a lot of cones, knockback, and a stun.
Archery: Smashing lethal damage with a bonus to acc. never really tried it.
Hope that helps
Helps a fair bit but I don't see Sonics in that lot
oh and;
Airhorns lvl 19
and Sgt. is lvl 10
Sonic is a little unerpowered compared to Assault Rifle because it debuffs an enemy's damage RESISTance - therefore successive hits will do more damage (the debuff lasts a bit longer than the average defence debuff too).
Personally I've found Sonics useful as a defender because anything that debuffs an enemy is a good thing and you don't have to be a powerhouse as a defender.
As a blaster though, imho, you should take an assault secondary power (such as energy or fire) to stack up the damage. So, you're on to a good thing by putting more accuracy into your primaries. Devices, unfortunately, is a very control-oriented secondary which works for powerful attacks such as Assault and Fire, but with the debuffing sonic and ice makes you feel slow and useless. However, as you progress and start factoring in DOs and SOs you should find your primary draws on the level with secondary.
Plus you get the excellent Siren Song which actually puts enemies to sleep. Word of advice though? Don't go for the knockdown blast. It's fairly pointless. IMHO of course 
Oh bugger, knew I forgot one 
Anyway: Sonic: has resistance debuff so more attacks=more damage being done. Not quite sure what the damage type is, never used one. Check your combat tab and see. Oh, and sleep? ick! Why would you want a status that cancels at the first attack? If you play with pick-up-groups and not people who know your powers and how to play to compliment them, I would avoid sleep like the plague.
EDIT: Yay, nofuture is back. Smashing/energy damage for sonic. Remember, shriek is minor damage, slug is high. Slug is, according to a build planner, about twice the damage of shriek anyway. So basically, AR is better than Sonic 
But I do know for sure that AR has better effects, better damage, and a better acc. The levels increase the damage done, and the enhancements don't really matter much until lv 22. Get them at the same level, and then compare, will be a bit more even by then.
OH: one more thing. Moves with more than one type have 2 numbers for each type, which is 12 then 12.
Ok, that makes thing a bit clearer I was just having a bit of trouble compltely understandinding things and in regurds to Devices yeah I realised I'd mucked up at about lvl 8 but decided to stick it and see if I could make it work. Bout the only thing from Devices I've taken extra from devices was the targeting Drone.
It's not that Sonic doesn't do "straight up" damage. What you're probably seeing is the two different damage types - Sonic is Energy and Smashing. Both happen at the same time, but if you look in your combat tab, they'll be displayed separately.
Assault Rifle is actually one of the lower-powered sets in the game right now (in part because it does mainly Lethal damage, which is highly resisted), but it has an interesting bag of tricks. It also has higher innate accuracy, which is to make up for the time you spend drawing your weapon. Since you've not hit single origin enhancements yet, this is quite possibly why you feel like you're missing on your Sonic. Once you get those in, I really doubt you'll notice any difference at all, especially with Targetting Drone slotted for to hit buffs - and anyway, it's not really that Sonic has low accuracy (although there was a rumour that it did for some time - the cone/AoE attacks do, like in most sets, but the single target ones apparently don't), it's just that Assault Rifle has a bonus.
If you want sheer power out of a Blaster, /Energy and /Elec are the ways to go (And most primaries will work alright, but Assault Rifle and Archery will slow you down since you have to draw a weapon). Devices works better if you want to stay at range, and play around with the mines and other tools in the set.
Sorry this may be an obvious question to you Vetran players but have been wondering about the major differences between the element types effects and what are the benifits of each.
For example Airhorn my Sonic/Gadget blaster seems to be very poor at hitting most targets and I've included a lot of aim bonus' to my slots and that non of his attacks does straight up damage, like my shriek power will now genrally to 12 points followed by 12 points.
Where as Sgt. Longshot my Assult Rifle/Energy Blaster will do around 36 points with his Slug ability and hits most times.
Thanks all