Nah, I have had no problems with Dexcool in my 1995 Blazer.
The problems that the cooling system had was due to the following:
1.) Parents not changing the coolant until I did in 2002.
2.) After that a rad cap failure allowing lots of air into the system.
3.) Improper dealership flushing. They didn't flush it long enough, one of those quickly 45 minute flushes.
The the overflow tank is filled just below the overflow tube and the air contact minimized, you should have no problems with Dexcool.
Most if not all of Dexcool failures is due to lack of maintanence or a hardware failure.
I also find short trips and city driving VERY hard on Dexcool.
Anyone with a Dexcool system should overfill their overflow resevoir and if you owna 3.4L, you should have the intake gasket checked. Some years had failures.