Spend as much as you can afford if you plan to keep it for a long time. The large patio cleaning heads are great for keeping the overspray down but I think they need the larger models to power them.
Quality is a bit hit and miss until you get to the pro models. The domestic stuff has lots of crappy plastic parts that although replaceable are annoying. Also be careful about storing it above freezing.
Spend as much as you can afford if you plan to keep it for a long time. The large patio cleaning heads are great for keeping the overspray down but I think they need the larger models to power them.
Quality is a bit hit and miss until you get to the pro models. The domestic stuff has lots of crappy plastic parts that although replaceable are annoying. Also be careful about storing it above freezing.