Ace,
Payouts: I've collected money from both of these books without issues. Cheques and money transfer services like Moneybookers which you may not have available. I will call them equal there.
Lines: I think 5 Dimes is more useful for my betting work. The reduced juice option is huge for me since I bet alot of hockey and baseball. I could have several bets a day on hockey at 5 Dimes and only a few a year at the Greek. For other sports though the reduced juice at 5 Dimes is also valuable of course although they can be uber sharp and an even a slightly stale line at the Greek may actually be better for basketball or football. However, overall I give 5 Dimes the nod as in many circumstances the reduced juice has to be more valuable.
Number of bets---I think 5 Dimes wins here too. I'm not reallys sure as it is not something that has affected me much. But I do think they have more on NASCAR or Formula 1 which I dabble in. But posters that I read like the vast menu 5 Dimes has compared to most books.
Limits: Greek is better here. 5 Dimes incorporates delays which can be a problem as well as not too large a betting limit. 500 on reduced juice and maybe a 1000 on other bets. Greek has higher limits and never a delay for me even playing things like Right Angle. Greek did put a limit on my bet size but no delays which is more important to me.
Hope this helps.