nope I dont (on my normal computer) for quite a few resons but I wont list them.
I do like how they have added User scripts (firefox uses can achive the same thing through greasemonkey).
for those who dont know what user scripts are there javascript which runs on user defined pages the uses for this is just amazing.
eg Im developing a userscript for GM that allows you to edit the css of any page and save it and have it auto reload when you next vist.
anyway I find opera is a good alternative to firefox , I use it on my mobile because its way faster than the defult mobile one and small screen rendering