Hi BFL13,
Choice of controller ought to be dictated by features and price per watt (or amp for those of us who may be wattage challenged).
When I was doing my system, cost per watt for panels was $6.50. MPPT made sense. Now it is under a buck per watt for panels, so PWM makes sense. I do insist that temperature compensation be at the battery--and I'd be willing to pay extra for that.
Today MPPT makes sense if, and only if, the roof structure does not have enough room for the wattage that the owner wants to have. MPPT will harvest about 8% more per day. Some folks also say MPPT will start charging earlier and keep charging later in the day--but I've never seen documented evidence of that.
