I purchased this tool because I wanted an OSS and a stationary belt/disc sander, but for space and cost reasons, could not really justify both. This tool does a reasonable job of replacing both tools, with a few compromises. The spindles available for this are somewhat shorter than the ones available for an OSS, and the largest spindle is only 2" in diameter. A dedicated OSS would allow for longer and larger diameter spindles.
Changing from belt to spindle operation is a snap. There is just one thumb screw to remove, and the whole belt assembly comes off. Replace it with a spindle, and you are done. There is a plastic insert that fills the space where the belt was during spindle operation. This needs to be leveled with alan-keyed screws provided before initial spindle operation.
Periodically, it is a good idea to remove the belt or spindle, and vacuum the tool out. there is a small fan that sits below the drive shaft, and is intended to blow sawdust away, but it is largely ineffective.
Overall, I am very impressed by the design features of this machine. Included in the many nice features are, the tilting table, miter slot, integral attachment storage, removable stop, and dust collection port.
The machine has an induction motor, which I found to have ample power. I did not try sanding a 4x4 along the lenght of the belt, but I have not noticed the motor bogging down in normal use.
Well I can't think of anything else right now. Overall I think this is a well built machine that is well worth the cost, especially when compared with quality hand-held belt sanders or dedicated OSS machines.