Default [Q] start with .58 or .84 for new rom???

Hi, I 'm a new member but i have been lerning and trying things from threads and post here for more than a year....I want to combine what i learned into a nice rom with good performance based on stock sony.
My main question is on what sony firmware to start....I was about to start with .58 enanched v3 but i saw yesterday .84 firmware with 86 baseband vodafone version posted here and i want your opinion witch would the best to use as a base for my rom.
every opinion will be usefull but please post a reason too, not just "use .58" or "use .84"