I bought a D75 2 years ago to replace an aging Gerber plotter. The plotter cuts very well, even super small stuff, and the OPUS is wonderful. The tech support is VERY responsive and willing to help with any issues. Plus it is a local company (to me anyway) and I really do recommend the plotter to anyone looking for a good, inexpensive but quality cutter.
However, there are a few things that caused me problems.
1) Out of the box, it is terrible at making paper patterns. The plotter constantly munches the paper on anything over about 2'-3'. I tried basic plotter paper from my local vender and the nicer EZ draw from Fellers and found no difference. I never had this issue with my old Gerber (Mutoh-rebrand) plotter. In comparing the two, I believe it is the way the machine drops the material almost straight down to the media catch basket. The paper hits the bottom but doesn't roll, instead kind of binds straight up and down causing a munch. I took the profile from my old Gerber - which does not drop the material straight down -- and made a "ramp" out if a piece of 3mm Sintra and that seems to have taken care of the problem; that along with slowing the speed down about 50%. Unfortunately I still have to babysit the plotter when I do paper patterns, but the munching has decreased by about 80%.
2) I find the plotter has issues when using smaller pieces of vinyl. If I stick in a 2-yard piece of vinyl, I sometimes run into similar issues as with plotting paper above. The vinyl goes stright down and hits the bottom of the catch basket. Sometimes is then falls into a nice roll, and sometimes it binds at the bottom, causing it to become stiff and this can cause it to munch in the cutter. the ramp I made for paper patterns does help though.
3) small gripe: the power button. Why put it recessed and on the back, jumbled in between the power cord, communication cord and lever for lowering the pinch rollers? It's near impossible to lean over the catch basket, over the front of the plotter looking at the back of an all-black machine, black cords and black recessed power button. Why not on the front where you can see it?
Anyhow, sorry for my gripe. The machine is worth the money, but it doesn't seem like it has been fully tested or something. After 2 years, I still don't feel comfortable leaving it alone to cut and vinyl longer than about 2-3', which is sad. I never had to babysit a plotter before.
EDIT: I too dealt with Phil and he was very responsive and helpful and even let me come in a try out the plotter before buying it.