I bought an H1 when this thread got started. I had been wanting to build a 3d printer for a while and all this excitement pushed me to jump in. I was really interested is what a cheaper kit could deliver.
First off, the documentation is terrible, but the yahoo group and wikis really help. I didn't get the bearing upgrade. The big problem with the stock bearings is that they are really out of round. Another problem is the axle shafts. The bearing kit still uses those plastic axles which isn't the greatest. I turned my bearings true using an arbor and cut new axles from 1/8 inch brass rod. The brass rods don't flex when you adjust the bearing tension with the screw. I also turned a new larger bearing for the lower position of the bearing block to account for the smaller size of the stock bearings I turned true. Linear bearings would be a great upgrade.
My kit was missing 2 sections of 12" all-thread that form the bottom of the frame. I had some rod that I could cut down and use. The rest of the construction went well. Even with my trued up bearings, there is significant slop in the bearing blocks. The initial prints show this. Another area is the backlash. Not having real bearings on the belt drive limits how much tension you can run to limit backlash.
The 3 axis board really requires work. The diodes on the extruder motor pins need to be removed or the pulses look like saw teeth on the oscope. There is no plug included for these pins in the kit. I had a plug from a computer CD rom to sound card that worked. The opto isolators also need to be by-passed or your prints will look like a leaning tower.
The file on Seeme's site doesn't have the correct parameters for Mach 3. I used 800 steps per for x and y. 64000 for z. Rapids are 900 on x and y and 8 on the z. My extruder set as the A axis is at 1950 steps per and 30 ipm. Your results may vary.
I'm using Slic3r for my g-code so I set my extruder to run as the A axis. This is nice because the extruder will reverse. Slic3r also generates g-code quick.
Overall, this kit is a great start and a platform to improve upon. These kits are not for those who are afraid to modify, improvise, and adapt.