Second, do you have in mind a certain truck like a king cab vs crew cab, 2wd vs 4x4, desired trim level, etc...?
The only thing I don't really like about my truck (SV without VTP) is that I can't adjust the height of the seat. I solved that by raising it using longer bolts and a stack of washers, heh.
Everything else, um... I like the truck and have had no issues.
Only common thing that seems to be an issue on the 2011+ Frontiers is the rear axle seal leaks occur a little prematurely. Seems to average 60k to 80k miles. You can prevent that using multiple cheap methods, people will argue for/against various ways to do it though. Seems the two most popular ways is to either do the "axle vent mod" or just replace the stock axle vent every couple of years.
Biggest thing to consider really is the model vs features. I personally recommend you compare a truck with utilitrack and backup camera to a truck without those. You will probably decide you do want those features, which means going for at least an SV with VTP. for the model.
Yeah I'm pretty solidly looking at only SV with Value Truck Package (VTP, I presume!), or a Pro-4x that's used. I want the LCd screen, backup camera, spray in bed liner, tie down system (very nice!), and so forth.
I'm looking 2013+ mainly because I want the LCD screen with blue tooth audio streaming, etc...for my music. Any idea of you can swap one of those radios in easily to a previous model that only has bluetooth phone? That'd open up a few nice older Pro-4x's for me price-wise... as I've been avoiding any without the LCD screen.