Instant film is so much fun to shoot that over the years I've collected a variety of instant cameras so that I could try all the options. Currently, the film choice is between the new Polaroid and Fuji's Instax films. Nostalgia makes me lean toward the venerable Polaroids (even though the film is a recreation of the originals) but Instax is the preferred option in most cases.
Here are all the films:
The worst of the lot is the LOMO Instax Wide model. Most of the photos I take with the Wide are unsharp, badly framed, and poorly-exposed. It's a giant, awkward camera and isn't much fun to lug around and use. This is a shame because I do like the larger images.
The original Instax film is too small to be very useful, but it's still fun and I make a lot of them. I like my Mini 90 "Neo Classic".
I also print digital photos (gasp!) on the mini film using an Instax printer, which can be fun.
My favorite Instax camera is the Square SQ6. It's not too big and not too small. The lens is reasonably sharp and the camera is simple and handles fine. I love the square format. Too bad the film isn't just a little bigger. Instax film currently runs about $0.90 per exposure.
One of my favorite cameras (whether film, digital, or instant) is the Polaroid SX-70. I want so badly to use the SX-70 more often, but the film is slow (however I did mod it for 600-speed film), and the results are often not great, honestly. The camera can be fiddly to use and it's very old (mine is from 1974) and I worry about breaking it. Add to that the cost, which is currently around $2.50 per exposure, and the SX-70 has been relegated to a special occasion, outdoor, once-in-a-while just for fun camera.
I also have a Polaroid OneStep2, which is much easier to use than the SX-70, uses faster film, and has a built-in flash. I get more consistent results from the OneStep2, but it's not nearly as fun. At $2.00 per exposure, it needs to be fun.
Shooting instant film of any kind is romantic and tangible. I love being out with family and friends and giving them prints right on the spot. I often find the prints later pinned to a mirror or stuck to the refrigerator in their homes.
Each instant photo is a tangible, immediate, one-of-a-kind bit of art.