I think we've finally decided to take the plunge and get self-levelling fitted to our Travelvan. But what sort, electrical or hydraulic? Which brand? I've read all the existing threads and it seems that hydraulic is the most popular and Doncaster seems to be the place to get it but I'm more than a little perturbed by the numerous reports of E&P rams "dropping". MaVe claim their system has a lock to prevent this. No-one seems to mention the electrical variety which not only appears to be cheaper but presumably is immune to "dropping"; is there a problem with these that I haven't heard about? Most hydraulic systems seem to be in the same ball-park price-wise so how do you choose? What pitfalls should I be looking out for?