Older Acer Iconia Tablets,
Be sure to pay attention to which generation of Acer Iconia you are looking at as Acer is relatively quick to drop support (and therefor the ability to update Android) to their previous models.
My Acer Iconia 5 is working great however, I am unable to update the operating system because Acer has decided they they rather sell us a new model than spend any more time on making updates to the ability to upgrade its operating system, so eventually the machine will run fine, but won't be compatible with anything