If you are going to run 300w on the Eco-W MPPT, do it with two 150w panels in series. I've seen that configuration and it will push 20a on a good day. I have also seen 300w in parallel and he never gets 20a. (both set ups were in use over a year)
Eco-Worthy does have PWM controllers.
This one for $48 has a LCD display and a hook up for a remote temp sensor.
This one for $56 has looks pretty basic but has the same metal body the MPPT controller does and it looks like you can hang some pretty healthy cables on it.
Other than they exist I can't say anything about them. BFL would be the one to ask about ebay PWM, he seemed pretty happy with the last one he had.
