>>3788451I spent months making an instax adapter for my RB67 and I don't really use it much. The problem is instax film has the dynamic range of a potato and you get color shifts on over and under exposure. It is fun getting tack sharp images with lots of bokeh on instant film, though. Being able to do long exposures is neat too, though the RB67 doesn't have a real bulb mode.
The RF70 seems really nice but not worth the price. TL70 build quality seems a little chintzy but it takes some nice photos. I don't really think it's worth the money unless you have a specific project in mind.