Pre-ordered both, and since I don't sell or trade in video game items, technically I've been using both since they became available.
I stopped buying games for the 3DS in 2012 and it generally sees no use. I did just update the system and might use it this week (My French Coach). I did have quite a bit of fun with it that first year between the 3D camera and the social functions (Street Pass).
Between Virtual Console games and DS compatibility, there's enough entertainment value in my 3DS to last me for years if I had absolutely nothing else to play with.
The PSV really hasn't been seeing much use other than for a game of Stardust or MvC3 although I did play around with it a bit and updated the system when I started using the PS4. Tight hardware integration although I don't know about using it as second controller since the DS4 suits me so perfectly.
Last thing I bought for it was Persona 4 on the PSN Store (Summer sale) and I've yet to actually install it.
Can't really place a numerical score for either handheld since it's really the games one plays on a given platform, if not the added features and functions that make it worth playing with for things other than games. I suppose one could rate the libraries, in which case I'd say there's more diversity for the 3DS across age demographics whereas the PSV feels more constrained, even though the library better suits someone like myself.
If we're just rating the hardware itself and the basic functions (not the games), the PSV gets higher marks for comfort, visibility, build quality, input with no mention of the specs or hardware capabilities, which are not comparable. My 3DS has a floppy hinge, one of the feet fell off randomly and was lost, one of the speakers was dead from the factory when I received it. Speaking only from my own personal experiences with one sample, the 3DS has had the worst QC of any piece of Nintendo hardware I've owned (various Game & Watch, NES, SNES, Gameboy, Gameboy Advance SP (2), N64, Wii).
