If your friend not going to be playing on the DSi, I'd recommend the EDGE. Unlike any of the other flashcarts, the EDGE has had no widespread hardware or software problems. Just about every card has though. The Acekard, CycloDS, DSTT, EZFlash, etc. So when you get this card, you know that you'll get a reliable card. The build quality of the card is very good, and the slot isn't springloaded so it won't break down overtime. It also has all of the features of the good features of the Acekard 2, along with slo motion. The game compatability is around the Cyclo DS' compatability and the menu, is good. Even though it is basic, it is still fast stable and it loads games quickly. You can also skin the menu if you think that the default looks ugly.
So all in all, it isn't flashy or anything like the other cards, but it is very cheap in price, and it does exactly what it's supposed, and that is to just work and play games reliably. It's a very reliable card.
But there is no EDGE card available for the DSi though. And EDGE would likely cost around the same as an Acekard. If you need to get a DSi flashcard, get the Acekard2i and call it a night. It's the only card on the market for the DSi that is worth it if you want a cheap card that just works. The Supercard DSonei is good, it has the most features out of any card, and with enough tweaking it could be come fast enough to hang with the big boys, but it's not as cheap as an Acekard, and it's not a pick up and play type card.