I have both of these machines. The monoprice mini is a nice machine. It comes completely assembled and you can actually be printing within 20 minutes of opening the box. It prints a little slow but good quality. The real downside to it is the 120mm cube you can build in. And because of the style of chassis it is not real friendly to upgrades and growing the build size. The GEEETech on the other hand takes some work to get it assembled:
http://www.digitalcorvettes.com/foru...d.php?t=269457
But once it is together you have a good understanding of all its components and how they go together and upgrades will go down easy. And the GEEETech takes very nicely to the upgrades. I have printed upgrade parts for my i3 I got the screen upgrade for cheap from ebay, I did the auto bed leveling and converted to an aluminum bed. I changed all the stepper drivers to drv8825, And I have every intention of getting longer rods for the y axis and a 300x200 heatbed. You can also easily convert the i3 to dual extruders. When you build it yourself the sky is the limit. or better, your imagination. The GEEETech is definitely the more robust and versatile machine of the two.