This thing is SO picky about lighting. The lighting has to be absolutely perfect for this camera to get a good picture. Here are three types of lighting I've dealt with and their results;
Sunny! A bright, clear day is the best time of the day to use your instax 210. This is the only time I've gotten results I'm truly happy with. These pictures are exactly what I love and expect from an instant camera. The colors are beautiful! If every picture taken with this camera looked like these I would be the happiest little girl ever.
Dusk! The camera doesn't do well in this lighting or similar lighting (like cloudy days.) In the four photos below it was dusk. The flash overwhelmed the subject in the first photo. In the second one I was too far away (maybe 35 feet) and the flash made everything appear dark since it didn't reach the subject. In the third and fourth photos the flash reached my subjects but makes everything else appear dark. I've learned to just put the camera away at dusk so I'm not longer tempted to take photos like this.
Inside. The first photo was taken in my craft room, and was the very first picture I took with the instax 210 (disappointing!) I'm still not exactly sure why it's so blown out! The other three photos I also have an issue with the way the flash made them look. The lighting in my house isn't that terrible and I made sure it was suitable (opening all the curtains, taking a test photo with my digital camera, etc) before taking the photos. Unless your house has lots and lots of natural lighting, I wouldn't recommend taking many pictures inside.
The camera also came with a "close up lens" which I have found doesn't really do much. I haven't used it more than the photo below and the last one in the photo above (rayray holding the rat.). I'm not so sure it's a great idea to even have a close up lens when the flash is so powerful, unless of course you were taking a close up outside on a really sunny day.
(according to fujifilm.com) on this camera is a pain my butt. It seems to be at the core of all my issues with this camera. When originally researching the camera before purchasing I noticed a lot of reviews said they didn't like the flash, wish they could turn it off, etc. I definitely agree.
An instant camera that I can still buy film for automatically wins points with me. Instant cameras are simply irresistible to me. The size of these photos is absolutely perfect, you can see a size comparison to the instax mini's photos here.
Simple conclusion- If you're looking for an instant camera that you can easily find film for (online) than buy the 210's little sister the instax mini.
If you have the mini already and are looking to expirement with another instant camera, buy the instax 210. The photos that do come out good are worth the frustration of the bad ones.
A word of caution before I end this- buy from a reputable seller. My instax mini recently died on me (after only 2 months of use but please don't let that ruin the camera for you, I have yet to find someone who has had this happen too), although the instax 210 has given me no problems as of yet it makes me nervous that it might do that same. Make sure the person you buy from has a good return policy and would exchange it if it bit the dust.
Hope this helps!
just a note; these are simply my opinions based off my experience with the camera.