I had a 2011 MBA and now have a 2013. I would say the new machine is about 30% faster, so you might see a bit more improvement over a 2010 model. If you get the big SSD on the 2013 MBA, it is way faster than the old ones. I get 700MB/s write and over 700MB/s read on my 2013 machine with the 512gb SSD. I think those older machines were more like 200 MB/s. I suppose it depends on what you are doing as to whether you'd notice the difference though.
Also, you can now get 8GB RAM in the 2013 MBA. The max was 4GB on the old machines. That might also make a difference. Then there's USB 3 on the new machines and an SD card slot that's faster too.