I've been with Site5 since 2003 and wouldn't dream of moving away from them! Their support is great from the most basic hand-holding through to very technical support queries.

At the moment they have an offer on for a reseller account going at $20/month with a $100 rebate so really it's $11.67 per month. For a reseller with these features, I don't think you'd mind the cost at all!

If I remember rightly, only the 'primary' domain will have wildcard subdomains enabled by default. However to enable it for a resold domain just takes a quick support email and they'll set it up for you straight away.

Also regarding the community/forums, that box is ticked: http://forums.site5.com/

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