Retroid

I have the 3 and I think it's a great handheld, but it is nowhere close to being able to play GameCube Zelda at a stable framerate (the 3+ is of course better, but I don't think it's significantly better). I've only tried one PSP game but it didn't play amazing. You'll have an okay time if you like turn-based RPGs. But I think if those are the consoles you're after and you like action games I'd get something a little pricier with a better chip. You can also just wait for the tech and price to reach a goldilocks zone, these handhelds seem very popular right now and are being innovated on constantly.

I have the 3+. Most PSP Games I tried run nice on 2x native resolution. Can’t tell you much about the GameCube games, tried one GameCube Zelda and it ran good. Not perfect, but playable. Can’t tell you about other ones.

I have a 3 upgraded to a 3+, but I think if I were buying a retroid for the first time and didn't know any better, I would have found myself leaning towards the flip. This is because I adored my clamshell Nintendo handhelds back in the day, and I baby my devices enough to convince myself I might be able to avoid hinge issues. I would be really torn over the sliders, though. Truth is that you can't really go wrong with either. I'll list out the Pros and Cons for each that I know of. Maybe it can help you decide...

Flip

Positives

• Clamshell means safer and smaller in your pocket. (No need for a screen protector or case)
• Black bars on 3:4 content is less intrusive because the screen is separate.
• The dual analog sliders have room to be inset enough to be more comfortable.
• The analog triggers are good for gamecube and streamed games.
• The design makes the system feel more like a dedicated gaming device than a modified phone with buttons.

Negatives

• You have to be vigilant about not stressing the hinge.
• The hinge doesn't bend as far as the DS or GBA SP did.
• The analogs are sliders, and I heard they don't click unless centered.
• (my personal opinion, but) the M1, M2 buttons are kind of weird.

3+

Positives

• It's got that PSP feel.
• The analog sticks are pretty good.
• If you get the grips for it, it's actually pretty comfortable.
• You can take it apart and modify it pretty easily. (Not sure if the same applies to the flip.)

Negatives

• No analog triggers.
• Dual analog games can get uncomfortable pretty quickly without grips.
• You might want to get a screen protector and a sleeve/case.
• The start/select/sound rocker buttons are all pretty weirdly placed (though you can get used to it).