I found the ESB malt to be much more full bodied, darker, and maltier, if that makes sense. I'd consider it more of a Marris Otter alternative than a 2 row pale alternative. The issue I had with it was purely physical for me. I found the beers I brewed were more "filling" than I was used to. Literally I could not drink those beers at dinner or in multiples because I felt like I'd consumed a meal. This happened with two different recipes. I'll try it again I'm sure, though.
Otherwise I had no complaints about its flavour, performance, etc. Who knows, maybe the difference between the 2 row and the ESB is purely the malting process. There is definitely a difference though. I'll take a look at the Gambrinus spec sheets later and see what the specifics are.