All of mine are with progressive. No mileage limits etc. I think my corvette is $90/ 6 months and would be cheaper if it wasn't the 5th vehicle and on a second policy by itself (they only allow 4 per policy). My camaro was under $70 /months when it was on policy 1. I don't like the restrictive collector car insurance (only drive on certain days and certain range form home, etc) so I keep everything on a standard high limit policy.
My 51 Crosley Farmoroad is with Grundy ($10/mo for 10k in collision. The the only limitations are commuting to and from work etc. its unlimited pleasure mileage. The big advantage to collector car insurance is the mutually agreed upon value.