We sell both Rolands and Mimakis: I would say Mimaki has the upper hand with these, but Roland has recently come out with a new model (MO-240) and seems to be trying to displace Mimaki in this particular niche... If you will be exclusively printing on acrylic, make sure to get an ionizer bar (an additional accessory with Mimakis) to control static as that can be an issue with acrylics...
Mimaki UJF-3042 MKII e
Mimaki UJF-6042 MKII e
Mimaki UJF-7151 Plus II
Roland LEF2-200
Roland LEF2-300
Roland MO-240 (new machine)
Mutoh also makes small flatbeds, but they are the poor man's version and definitely do not have a good reputation...