My first toon and main is an Energy/Devices. He is very dear to me but I have learned lessons along the way with him (see My main is uninspiring (Energy/Devices) - what would you do?). The two greatest things I've learned is that nobody but the solo'er likes Knockback and that the Devices secondary sucks.
I'm not trying to talk you out of trying it out. Sometimes I try out a power after reading in the forums how hard it is to play - just to try it out (/Poison, I'm looking your way!). It just might be overkill to give it to both of them. I highly recommend using Devices on any toon you wish to solo. But Devices is a little lame on the "oomph" and doesn't offer as much benefit as the other secondaries.
If you are new to blasting, lose the /dev or you'll never know what they can be like. I've parked four AR/. I love the concept, but the execution is flawed. Full Auto is not worth is with things like M30 and Beanbag being skips.
What in /dev do you want? The pet is lame. Caltrops is about the best thing there cause you can proc it up. You don't have enough time teaming to use either of the mines. Hmm, targeting drone is good.
The best for beginners, and actually probably the best, is fire/ice, and yes, I do skip at least half of ice, but that's so I can mule concealment for LotG+7.5s. Archery is also something nice to have around, but I can't go for it. Or DP. Ice/ice is unique.
Roll everything. See what you like. For a beginner, no /dev, no energy/. AR's not bad, really, but it's on my do-not-want list currently. [though I just rolled a AR/Ice this week.]
Edit: I've taken two AR/Devs into the 40s. My first one I deleted when I discovered she wasn't going to get any better. Then rerolled her as a DP/Energy and abandoned her at 4. I still keep her to reserve the name. The other is at 41 and is an active marketer and runs my personal SG, with only her as the member and only enh storage inside. But you can't beat the Nemesis rifle, so cool.
TBH, I just put devices in there because it felt like it would fit the theme, as would energy manipulation. I spend more time in the costume creator than anywhere else in game. I'm slowly working on my Arachnos Soldier, but I also wanted a Praetorian since that wasn't around last time I played. I figure this is an excuse to take a concept character to 50 instead of just taking the easy (MA/WP Scrapper) way out.
My Dual Pistols/Dev blaster just hit 50 the other day. I understand the dislike of Devices, but it is not nearly as bad as many folks say . . . but I don't use some of the Devices powers much when teaming.
This was mainly a concept character . . . as soon as Dual Pistols was announced, I decided to make "Pepe LePewPew" mainly because I found the name amusing. He soloed a fair amount, but I have found that I enjoy setting up large groups of Trip Mines and then luring foes to their deaths. It is not fast, but the big BOOM is satisfying. I found Devices appealed to my strategic side more than my "Kill-em-all-NOW" side. I doubt that Pepe will ever get fully IO'ed up or get a full set of Incarnate abilities (too many other level 50's), but he was fun to level up.
My first Blaster was an Ice/Ice, who is still my favorite . . . but I'm mostly a controller at heart and Ice/Ice is virtually a Dominator without Domination.
LOCAL MAN! The most famous hero of all. There are more newspaper stories about me than anyone else. "Local Man wins Medal of Honor." "Local Man opens Animal Shelter." "Local Man Charged with..." (Um, forget about that one.)
Guide Links: Earth/Rad Guide, Illusion/Rad Guide, Electric Control
Trip mines x8 = trick or treating fun.
Takes a while to set up and is gone quick, just like fireworks. 
I think this is a good thread to get you rolling with a bunch of ideas for an old set.
Long story short I do think the OP Nethergoat had the idea down right. It just took me a bit to see it. My last post is a current build and it really, really has made this toon really fun again and honestly a power house.
ar/dev retrofitting project
1. Why Soft Cap is Important : http://dechskaison.blogspot.com/2011...important.html
2. Limits: http://paragonwiki.com/wiki/Limits
3. Attack Mechanics: http://wiki.cohtitan.com/wiki/Attack_Mechanics
4. Rule of Five: http://wiki.cohtitan.com/wiki/Rule_o...e_Law_of_Fives
Since the new Anniversary badge is out I've been on a spree to crank out as many concepts as I can so I can get them badged. Tonight I came up with two new blasters. Being that I have no idea how to play a blaster and may actually want to try and play one of these guys in the near future, I came here for help. I may make a few changes based on what is said here. So, here's what I ended the night with:
Public Enemy 2.0: The Clockwork Gangster (AR/Dev)
Gunslinger 2.0: Fastest Clockwork in the West (DP/Dev)
So, I literally had no idea what I was doing. I stuck them both with Devices because it fit the technology theme. I'm thinking of switching Gunslinger over to Energy Manipulation. I was also curious what the differences between AR and DP are. I will at least play one of these guys on a regular basis and knowing what I'm getting into helps. If I can get the ball rolling on these guys I think I could have a blast. Maybe put one on each side of the law and see where it goes...