Yeah, N3DS is great, but given a choice of emulation on the PSP or o3DS, you'll probably have a better time with the PSP. NesterJ, MasterBoy, and PicoDrive still work great; TempGBA4PSP and Snes9xTYLmecm_mod work great as well and they're still getting updates. I'd rather just use my PSP Brite instead of invest $150 for slightly better emulation. I'm sure I'd prefer a N3DS over my PSP as RetroArch is nicely polished on the 3DS, but I have an o3DS and don't think the investment is worth it.
I'm a big fan of the PSP. It didn't start out that way, but I got a PSP-3000 a couple of years ago and fell in love with it. It's so easy to hack, and the emulators run surprisingly well considering its age. It's frankly a little embarrassing that Nintendo's first stab at the 3DS doesn't measure up to the PSP in some respects.
I do have a New 3DS XL, but I'm hesitant to experiment with it the way I have my Old 3DS. RXtools would run better on my New 3DS, I'm sure, but the thought of accidentally bricking the machine horrifies me. So for now I'm just happy to use the Ocarina of TIme 3D hack and use the Old 3DS for heavy duty hacking.