Over the past 5 years I've had a total of four electric smokers. I started with the cheap bullet-style and worked my way up to a nice modified vertical electric that I thought I'd have for a while.
About two months I go I was on Craigslist and I found an ad for a Cookshack SM008 (slightly older residential model). The guy was offering it for a price I couldn't refuse. Since then, I've come to realize that the Cookshack will be in the yard until it falls apart (which, by looking at how it's constructed, won't be for a very long time). I got rid of the other electrics and when the time comes, I wouldn't hesitate buying one of these things brand new.
This thing is built like a tank, very well insulated, uses significantly fewer chunks than any of my previous smokers and requires little attention. No water pan to mess with, the wood smolders and never catches fire and consistently puts out great chicken, ribs, brisket and pork butts.
If you're looking for something that will last, doesn't need any modifications and puts out great food, I'd go with a Cookshack. It's a little more up front, but from what I've read, people have these units for a very long time. Great domestic customer support and parts availability from their headquarters in Oklahoma too!