I shall be the one to answer your question.
A small thing to note:
- Some flashcarts are recommendable thanks to them having "Official WoodR4 support" which really means little now seeing as Wood hasn't gotten updates in ages (mostly because there aren't any glaring problems, 99.9% game compatibility, etc.). Pretty much, if it's got the same game loaders as the last version of Wood (v1.62), official or not, they are all about equivalent.
- Wood is the preferred kernel since it is probably the 2nd most feature-filled menu besides the DSTWO and AKAIO.
- YSMenu is the last bastion of salvation for a host of clone flashcarts. It's most prominent feature is being next to feature-less. (It's got cheat support at least)
- If it's a clone, it's shit regardless of origin. (R4ids.cn included, though it's just less shit thanks to Official WoodR4 support)
The TL;DR run-down of the more reputable flashcarts:
AK2i: Contact issues across the land
DSTT: Old as fuck, and it's only saving grace is YSMenu, like almost every other clone flashcart out there.
R4iGold (R4ids.cn): Official Wood support, works and is recommendable. It's a clone though.
Ace3ds: Unofficial Wood support, still works. Maybe recommendable if it's cheaper and you give no shits about whatever small menu features were added post v1.42 or w/e. Game compatibility is supposedly still the same as v1.62.
DSTWO: The pinnacle of DS flashcarts. It'll fuk up your Slot1 (heil contact issues) AND burn more power for those features you probably won't use.
Original R4: 2GB limit, but otherwise equivalent to the R4ids.cn
EZVi: It's kind of spotty with it's extra features (but DOES have them), but the staple shit is as solid as any other flashcart.
Everything else: Probably not even worth looking at, you are just asking to fuck yourself over...