Nelson makes a quality rotor (5500, 6000, 7000 etc), Controller (Ez Pro, Ez Pro Max, etc) Valve (7900, 9500, etc). I am not all that impressed with their pop-up spray body (6300 series). I would choose a different brand on that, such as Rain-Bird (1800 series), Hunter (Pro series, or Institutional series), or even WeatherMatic (LX series). As far as the MP Rotator (by Walla Walla), I again am not as impressed. Rain-Bird Mp Rotors/ aka Rotary Nozzles are far superior in my opinion, although the MP Rotator have adjustable arcs, their rotation speed is often too slow (can easily stop rotating). I feel my answer is unbiased as well, considering I sell all of the products you have & I have listed. Best of luck!
More info on Rain-Bird Mp Rotors aka Rotary Nozzles....... http://www.sprinklerwarehouse.com/SearchResult.aspx?CategoryID=478
Josh
Irrigation /Landscape Lighting / Pump and Well Specialist