I would take Pharoah's opinion into great consideration m12.
The R4 was the second slot 1 that I bought, and it was indeed the number slot 1 flashcart for a very long time. But right now, because of lack of features/firmware updates, it is no longer. And I think of the biggest reasons to go with just about any other slot 1 flashcart out there is for microsdhc support. It's much more pratical to use one microsdhc than 2, 4 or 6 different 2gb microsd's. And trust me, you'll just keep wanting more and more storage as time goes by.
In my opinion the top two carts are the Evo and the SCDS1 for their features, compatibility, and great support. They're are both basically the same. If you want to spend more money than get the Evo, if you want to spend less, then get the SCDS1. If you want to spend even less than that(but keep in mind for less features), then get the AK2, or maybe the Edge.
I don't regret buying the R4 because it still does what it's made to do. But...there really isn't any reason to buy an R4 with all the other choices out there. In fact it would be pretty ignorant to do so.