Hi there!
Let me ask you, have you tried to check
any of the threads/topics before posting this question?!?!
There is even a topic for asking about witch flashcart to get according to your criterion......Try to search first next time!! You'll leave much better first impression!!
Now, on-topic.....no DON'T get R4 because it's dated and doesn't get any more firmware updates, and you'll have a hard time finding a real one, not to mention that all the left ones are clones and fakes probably!!!!
DSTT is a much better choice, but you should consider other carts, because there are better ones..
Look into CycloDS, probably the best cart you could get, but a bit pricey..
M3 Real Perfect bundle if you're interested into playing GBA games at best compatibility and extra features like GBA cheats and GBA RealTimeSave..
And check AceKard 2 for the best "budget" solution out there, also, very nice interface!