I'm doing out of town TI cycles and I use an imaging center for my u/s. No one ever recommended one, it was just easier to not have to deal with a local RE. I can't say they're "better" at reading the results though, but I will say they are more thorough- they look at everything. I'm usually there for 20-30 minutes as opposed to a quick 5 min scan with the RE. I'd say there are pros and cons. Biggest downside is that I can't do weekend monitoring with them. But with TI cycles I can work around that.
Best of luck to you!