it's not a software browser issue because a lot of people have noted ui lags and choppiness. It could be a software issue though in general. Problem is the ipad doesn't render twice the resolution and then halves it and in some res re-adjusts to fit the screen. There's a further problem in that ios is a very optimized os, it's a kernel above darwin, and it's where apple's dev. efforts are clearly focused. Sadly os x has been left behind.
Everyone in the market for a rmbp (I ve not pulled the trigger yet, but I am planning to, very soon) would like all this to be software related. But then another question arises. Will they be able even it's software related to fix their software enough? Or will this be forever a compromised first gen model and apple will do their usual os x trick of just throwing better hardware to the problem once new gfxs are out in v. 2?
Lion in macs, a few years old, has some choppiness in terms of ui rendering. That too is a software issue. The core 2 duos on which lion is ui dog on, dwarf the arms on the ipad. Yet the issue is there, it hasn't been fixed by software. Software is extremely hard to develop, debug and optimize. If apple aren't allocating enough resources, it simply won't be fixed. Even if they were allocating the appropriate resources to os x, that wouldn't be a guarantee that they 'd fix it.