How many 3ds games are you interested in? If there is at least a handful you definitely want I would say go for it. Especially if some of them have high replayablitiy.
If you are not enjoying your system there is no reason to keep it. Even if a few years down the line the vita ends up getting some great games you want to try, you will definitely be able to buy one used for cheaper than what you can sell yours for now. Heck with how poorly the vita is selling, you might even be able to buy one new for cheaper than it is today.
Just as an example I did something similar to this a few years ago. I sold my 360 2 and a half years ago for 200bucks when I realized I was hardly using it. There are a handful of exclusive games I'm interested in that came out since then. I will be able to buy all those games and a used xbox for probably under $100 when I have the time to play through them.This advice goes for any console/handheld. Prices are going down quickly for everything. Especially for the less successful gaming systems. So if you aren't using it, you will make some extra money selling it even if you rebuy your system a few years down the line.
