Hi Nick,
I have had a Pulsar dome for over three years, and it does the job well. There are no problems with leaks or other significant water ingress, but there is the occasional thin film of condensation on cold metal surfaces. Not really a problem, but I address it with an ELA DD822 Dehumidifier and Laundry Drier bought from Dry-it-Out.com.
http://www.dry-it-out.com/DD822-Graphite-dehumidifier
Running costs are not really a problem – it only needs a quick blast once-or-twice a week. I find it an ideal solution and everything is kept bone dry.
Very best,
Bill