jcarroca, I've been using a Dolphin Dynamic for about a year now. The upfront cost is somewhat high, but I haven't noticed any increase in my electric bill. Obviously it's costing me something to run it once a week, but it doesn't seem to be very significant. As for the unsightly power cord, it has a 65' low voltage cord that runs to a transformer which plugs into a 110V outlet. I don't think this is an issue, since it's only plugged in while it's in the pool. The rest of the week, it's stored away. I haven't used any of the suction-side or pressure side cleaners, but I would imagine the hoses are just as unsightly and even tougher to deal with.

The only downsides I've seen is the upfront cost and the possible need to purchase bottom drain cover(s). Mine kept getting stuck on the drains, so I bought a pair of Polaris drain covers. Pricey yes, but it never gets stuck anymore. You may or may not have this problem, depending on your pool. I can't speak for the other robot cleaners, but from what I've read the Aquabots seems to be very good too.