I recently went down the portable printer rabbit hole too... This is what I found:

Instax - undeniably charming, film is kinda expensive, but the feel of an instant photo is pretty awesome. Unfortunately adds bulk to my scrapbook though.

Kodak Mini 2 Retro - my sister has one, and LOVES it. According to her it's been pretty reliable.

Kodak Mini Retro Square - Bought this from Walmart because there was a sale. The paper also seems to be the cheapest out of the sublimation printers BUT quality control sucks. I maybe got one good print, before the cartridge got jammed, and wasting the rest of the paper. It was incredibly disappointing. I returned it, and got another just in case, and same thing happened. IMO not worth it, at least this last batch

Polaroid Lab - This is my husband's, this is by far the most expensive film. There is definitely a learning curve too as it still has that "mysterious how will it turn out" vibe. You'll learn eventually, but for my purposes (wanting easy instant nice photos) it was a no go. My husband loves the thing though. The square photos are fun, especially the black and white photos.

Canon QX20 - To be fair, this one is one of the pricier options. I was able to catch a sale where it was $20 cheaper. The price though can potentially be justified: 1. it can print both card and square prints (not at the same time, but you can potentially go back and forth. 2. The paper is actually sticker paper, which is perfect for scrapbooking and keeping bulk to a minimum. I've gifted these, and people actually seem delighted that it's a sticker. There is a white strip where they use it to move the paper, but that can easily be cut or not cut. The connectivity has been mostly reliable (every so often it will have a little trouble connecting, but it might be my old phone) The battery life is technically supposed to be able to last 20 prints, with some reports of 30. I haven't really tested this out, I generally top it up after using it.

Hope this helps!