Of course, if you still see any problems with this version, please get back to us.
The results that I get with updated iMacros are quite weird. In a fresh Firefox profile V8 Benchmark scores are as low as they were before (500 out of 3000 without iMacros). However, if I install Firebug, open its panel and enable the Script tab, performance improves considerably, though is still worse than with iMacros disabled (2000 out of 3000). Some of V8 subtests perform great, while others run slow. If after that I disable Firebug's Script tab, scores leap to their maximum 3000. If I restart the browser (Firebug installed, but Script tab disabled) -- scores are again very low (500 out of 3000). Tested both in Mac OS X and Linux with Firefox 7.01, results are attached.