I find real world use render times to be roughly same with Firefox and Sailfish browser. Close enough that definite comparison would require too much effort for me to care.Not really suprising considering that both are (AFIK) Gecko based.

The main problems with Sailfish browser are lack of landscape, oversimplifield handling of 'extra functionality' (history, boolmarks, etc) and buggy clicking.

The last one got helluva lot better after last update, but the last time I tried there were still moments when I was left cliking a link without any effect. It's extremly annoying when it happens and the only cure seems to be to close the browser and reload it.