I highly recommend the 8 Card packs
. First off most of the time, you'll make more Clintz just selling the unwanted cards than you would have if you'd bought the clintz, especially if you sell the 5 star. Almost all of them sell for at least 2000.
Secondly the 8 card packs
seem to turn up more rares than do the regular packs
. I bought 8, and got at least (on average) 1 rare per pack
, and a few I got 2 rares. Also the Uncommon ratio seems to be a lot higher on these packs
The downside is that if you're looking for a specific team then you're almost better off buying the 3 card packs
, as you're more likely to get that team, and I have gotten rares from those packs
, but far less often than I have from the 8 card.
Overall it's a better value as well. If you buy the 3 cards it costs you 60 credits to get 9 cards. With the 8 cards it's 50 credits for.. well 8.
And 5k Clintz won't buy you the same level of cards that you'd get in an 8 card pack
. (Nor would it buy you most of the 5 star characters, much less 7 others)