I'll second that: our previous camper and our new one both had / have the 3L. Fine on the flat or downhill, but put any sort of upward incline in front of them and 30 to 40 km/h is all you get with the pedal flat down. I've never driven anything else so gutless, but of course the weight has a bit to do with that. It can be very embarrassing when you see that line of traffic building up behind you and there's nowhere to pull over to let them pass.