While the first two entries from Fujifilm certainly won't win any sort of beauty contests, their third entry should tick the 'style' box for many prospective owners.
There are plenty of things to like about the mini 90: it uses a rechargeable battery, has more control over exposure, and looks good while doing it. It uses the same motor-driven 60mm lens as the mini 70 with the same 0.3m - infinity focus range.
The shooting modes and controls are a bit more extensive than the mini 70. On the rear the camera keeps a similar LCD display as the 70, although the 90 has gained a couple more buttons. The power switch has been moved to the front, and while the mode and self-timer buttons remain, the self-portrait button has been replaced with buttons for macro, lighten or darken, and flash.
That last button is important, as it may be one of the deciding factors for someone considering both the mini 70 and mini 90. This button enables the user to manually disable the flash. This, combined with the ability to lighten or darken the exposure gives the photographer more control for exposure than they would have with the mini 70.
This, in theory, sounds good, but the mini 90 has some ergonomic problems when it comes to real-world use. There is one shutter button placed on the front of the camera, surrounded by the power switch, meant to be used when the camera is held vertically.
There are three raised nubs on the back of the camera that resemble false buttons that act as a thumb rest. In this orientation the camera is slightly awkward to hold and not very comfortable. The mini 70 has a much more comfortable grip in this orientation.
The other shutter button is placed where its typically found on any camera: the right-hand side of the top plate. However, there is absolutely nowhere to grip the camera with the right hand while using this button. Trying to hold the camera with the left hand in conjunction with the right will block the slot where the image is ejected, and can crease the photo if not removed immediately after taking a shot.
Both the mini 8 and mini 70 are easier cameras to carry around without a strap. They both have places to hold the camera at the ready, and the less options and settings really mean the camera has more ability to get the shot right. Also, pro tip: the camera is more likely to not fire the flash in daylight when set to 'landscape' mode.