All 3 of those are as equal of eachother and fine for a homeowner DYI. I would hope no professional would use any of these controllers .
The sst has a slightly different programing format then the ism and e9c.. Other then that.. They all do they same thing
Probably out of your budget- but for you sean, I think you would really like the irritrol PC.
http://www.sprinklerwarehouse.com/Irritrol-Irrigation-Smart-PC-Controller-p/pc12-int.htm
WOW!

That would be awesome......but like you said, way out of the budget for me. That budget is about what I'm putting out to "refurb" the system. Remote is more of a convenience for my lawn. Since the valve boxes are never more then 200' away, its not much of a problem. Besides, when needed, some neighbors are always willing to help! (And get wet when they turn on the wrong valve for the area they're standing in)
I found 1 more by Rain Bird. It is actually labled under the "professional" section on their website.
http://www.rainbird.com/landscape/products/controllers/STPplus.htm
Believe it or not, 3 houses around here have the Rain Bird timers. 2 of them have the E9C, and the other one has the SST-900i. They were put in a while back, and had those timers installed......Different companies for each install too.......
They work pretty well. The SST-900i has a big flaw of a no "run all" function. Which I hated when I repaired a few heads for them.......Thankfully the valve boxes were easily acessible.....