Which model are you looking at, and what exactly are you trying to do?
I ask, as if you're after a 1:1 (disk per port ratio), then you don't need a SAS expander based enclosure. SAS Expanders are for adding more disks than there are ports on the RAID card, and you pay a performance penalty for doing this.
If you're doing video editing/animation, then you'd be better off with a non SAS expander unit, and it's cheaper too. There's also other companies you could take a look at, such as Sans Digital's
TR8X.
As per cards, you can go with ATTO, or take a look at Areca (better price/performance ratio, but ATTO is located in the US, so tech support is a bit easier to understand - both companies know what they're doing, and can actually support what they sell, as they actually design their own products, not use ODM's like Highpoint does).