At risk of providing too much information:
You're sitting at the nexus of one of the big rifts in the reefing community over the past 10-15 years. Manmade/dry rock vs ocean live rock?
Dry rock has a lot to recommend itself. It's cheaper, substantially so, and in a way that makes a huge difference when setting up a larger tank. Dry rock can usually be found for anywhere from $2-$5/pound; live rock typically goes for $7-$10/lb. Given that most people suggest stocking 1-2 pounds of rock per gallon of water, you could be looking at a difference of more than $1,000 to go with dry rock vs. live.
It's also easier to get dry rock in specific shapes. This gives a level of intention to your aquascape designs that isn't really possible with live rock. You can plan out several foundation rocks, arches, caves, etc., and plan out exactly how to aquascape everything without getting anything wet.
Finally, dry rock allows you to control what goes into your tank better. This doesn't matter so much to me (I fall more into the non-QT camp), but if you're planning on quarantining everything that goes into your tank, dry rock gives you an extra level of control that live rock doesn't.
Having said that, there's a reason that live rock is more expensive. It just seems to set everything up better for success. I've used both dry rock and live rock; when I started my dry-rock only tank, it never really got going until after I added in about 20 pounds of live rock as a supplement. There's something about the natural balance of everything in live rock that seems to really promote success in a reef tank. Can I prove it? No. If you ask me to define what that x-factor is I couldn't do it. But having used both, the higher expense of live rock has always seemed worth it to me.
You're not setting yourself up for failure if you want to primarily use Marco rocks. But if you do go that route, I'd recommend adding in about 20-25 pounds of live rock as a supplement.
