"What's your take on experienced hires? I'm at a national mid-size, and once I have my designation I was hoping to move into the big 4. Is it pretty tough to get established, or even to get into a big 4 at the moment?"
Good question. In the past, after 3-4 years at a mid-size or boutique, you could get in since there was always a need for senior associates/managers. At this very moment, it's highly unlikely. HR will have to come up with a darn good reason for hiring people from outside the firm when they laid off people at the same level just a few months ago. Down the road, it's very likely. It also depends on the firm and the location though. If KPMG Chicago is way short of seniors right now for example, then you have a shot there.
As far as transition goes, it's not that bad. It'll take a few months to get used to the different software applications, and i guess public companies since most publics have big 4 auditors. The biggest transition would obviously be the culture, but hey, where's the fun if it's the same monotonous culture across all offices right?