I use Google Apps for Domains Enterprise at my place of employment and have always found their support to be very quick and responsive.
My gripe is they always have Apps for Domains features after everything else. For example, I can't upgrade users beyond 25GB of storage even though this is available for normal google users now.
I'm also waiting for GApps to grow their size, but it's possible that the paying customers are last because Google treats them most carefully. Roll stuff out to your paying customers last, when you know it's solid.
This mostly applies to features, not size limits, but it could be behind their thinking in general.
My gripe is they always have Apps for Domains features after everything else. For example, I can't upgrade users beyond 25GB of storage even though this is available for normal google users now.