I've a little experience with CPanel. At the begging of this year i got a domain with a little hosting plan from a provider within my country just for fun beside having some experience and basically i use the domain for Google Apps(custom email). But i like DreamHost panel much more. Its unique. Its beautiful yet powerful and featured.
You said you've dozens of sites including small business sites. So i guess you've atleast a medium-big space and bandwidth need. You can count yourself how much space and traffic you'll need regarding how you need now. Always remember(i think you do) that your space and bandwidth need is increasing everyday. Therefore you maintain business sites(wheather small,medium or big). So you've to think the future needs in advance. If your necessity of space and bandwidth is near to 'crazy domain insane' plan i think you can get the 'code monster' plan. Because at this time there's a 50% discount offer with this plan. Again if you pay for two years in advance you'll get more 20% discount. So using a $97(if you want discount instead of extra valuable features) promo code you can get the plan @ approx. $190 for first two years. In my sense its the perfect plan for you now,unless you need more bigger plan.
You can do this through getting a you.dreamhoster.com subdomain at the first time. Then transfer your old files to DH. After your site is up and running then setup your domains.
You can either transfer your domains to DH or keep them on present register and just host with DH. See above posts for details about this. Good luck.
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