Both cricketers for me personally have epitomised what it means to be an allrounder, both in very different ways, have they succeeded and despite averages and statistics, IMO its very hard to sperate them. arguably you could look at Sobers and immediately say that he is the greatest we've seen, his batting was immense just behind the don's, bowling varied so much (extra finger might have helped!) , whether it be spin, swing or medium pace he had it, and his very underrated fileding as well.
Though as in general just on the basis on a cricket allrounder, its fair to say he is supreme, but as a test cricketer compared with imran, its a different story. Sure the bowling being supreme to imran, but despite sobers fielding and batting being considerably better than the latter, sobers does seem to have an edge, but for Imran his greatest strength was his captaincy. Tenacious captain who always gave 110%, and to consistency play for 20 years and at the end, retire with the biggest prize of them all is unimaginable, not to forget how his role helped in alot of new good yongsters who arguably are rated as greats now from pakistan i.e. the two W's and inzamam.
Overall, on the basis of a crickter, its hard personally to separate these two on my basis, they both have done wonderful jobs in different ways but in equal quantities it could be argued, thus for me I find it very difficult to seperate these two, sure you could look at other things such as records from sobers with his 360 odd and six 6's, but were not simply judging them on an allround position, more as a cricketer! Two great legends, two great warriors, they're inseperable!