You may feel confused about the r4i gold 3ds or r4i gold pro card. This post will just tell you the differences between them.
First, take a look at those two cards: r4i gold 3ds and r4i gold pro
First, they are released by different teams. r4i gold 3ds is released by r4ids.cn team which also released the r4i gold 3ds deluxe card for playing 3ds games, and r4i gold pro is released by r4isdhc team which also released the r4i sdhc dual core and r4i sdhc rts lite.
Second, the r4i gold 3ds card is using the wood firmware which is a very famous and great kernel for ds flashcart. and r4i gold pro is using their own kernel. Both of them are updating regularly.
Third, for the features, both of them are used for playing ds games and have very good game compatibility, you can use them play most of the ds games. the only differences for now i can see is r4i gold 3ds can play SNES games but r4i gold pro can not.
For now, i would recommend r4i gold 3ds more which uses the better kernel, update more regularly and has a better tech team. but if you don't need need too many features, r4i gold pro is also very good.
Do yourself a favor, don't buy crappy flashcarts.