Now, I'm going to come out and say right now I'm not the most tech savy person with computers, routers, etc. but I'm almost sure they aren't the problem in my case and wonder if I'm the only one who notices this issue on their Vita too.

So I've owned my PS Vita for almost 2 years now (bought it for Persona and the promise of FFX HD) and I love it, but... the internet connection on it sucks. I'll sometimes try using the web browser, Youtube, or PSN on it but it'll constantly cut off for whatever reason. I'll do an internet connection test and it reads fine and as soon as I go back to whatever I'm using that cut off it works perfectly fine. 

This doesn't happen on anything else I own, PSP, 3DS, PS3, Wii U, etc except maybe the Wii (but who really uses the Wii's internet?) All always work 100% of the time without problems. Is this a problem only I face? Is it possibly I have a slightly defective Vita? or something else, what do you think?

I have the cut down on PSN often as well. It's most likely not your connections fault.

I always get weird connection errors with PSN on my vita but thats about it. Make sure u are close to the router and u got good bars

in threads about remote play with the vita people often say that going to settings > power save settings and unchecking "use wi-fi in power save mode" greatly improves their reception quality

personally I never had wifi problems with mine with or without that option active though

I can try that and see how it works for me, thank you!

Make sure you disable the power saving feature, as outlined here:

http://manuals.playstation.net/document/en/psvita/settings/wifi_savemode.html

That setting caused issues with my connection.

It could also be a sign of your wireless router not being able to handle the load (either due to a failure or just being over capactiy).  

Sounds weird. I would call Sony service.

I have two Vita's, a 3G I use daily as a phone with Skype, and a wifi only model I at home. The only issue I have ever had is random issues while browsing the store. Chat sessions, Skype, Crackle, Netflix, Hulu, Youtube, etc. I have never had any issue with.

Try what the people above said about the power saver, but if that doesn't work, it may be something with your system. Have you ever rebuilt the database? I had some network issues with my PS4, and that fixed the issue.