We had a number of problems with the 1000W digitals. In the first 5 months, we were using 8 units, and we had 3 fail, so we discussed these failures, along with the heat issues, we decided to go with the 600W digitals.

We have been using the 600W digitals for @1 year and we did get slightly lower yeilds (@5%less), but our power bills were 50% lower than the 1000W digitals.

My fealings are that the 1000W digitals still need some serious engineering work to resolve these problems, while the 600W units work great!!!!