Here's what I think:

If you are really serious about SEO and Website Marketing than you really need to do your own research and come to your own "informed" opinions.
I would suggest you start by purchasing a recently published book or see if you can find one at your local library.

The problem with doing all your research on the net is that you will likely get hundreds of conflicting ideas from anybody and everybody. Also, many of the people giving you advice may have ulterior motives. see more

As for sticking with Dolphin 7, this is also a decision you will have to make all on your own. Personally, I haven't seen anything better. I'm with Dolphin for the long haul.

Once again, keep us posted. Looks like you have some important decisions ahead of you. I'm curious how things work out.