we demoed a Komatsu D61i with the built in GPS last summer against a JD750J with the Antenna's on the blade. Not having the Antenna's seems like a great idea but I am not sure how the sensors in the cylinders will stand up on the Komatsu. Has anyone put many hours yet on the i series Komatsu's yet. The D51's according to the dealer will now only be available with the built in GPS. I am guessing that Cat and JD will follow soon with antenna less systems. Doug
Curious about the same thing. We have one 61i machine and 3 61-15's. They are great grading dozers especially on 2:1 slopes, however we do trade them in around 6-7K hours as they just dont seem to age well. The undercarriages on the -15's have been dissappointing as well, supposedly they have fixed the issue with the -23's tho. I think the i machine has around 2k hours on it without any issues.
We put 500 hrs on a d61 with the gps no antenna on the blade. Worked great, less set up time. We did have Komatsu come out to adjust the speed of the blade grading. It didn't do so well in 2nd gear, now it is fine.