Omega is the highest cost brand of the three you've listed. I have them in several finishes and all are fabulos. You can mix Dynasty and Omega (if they sell one they sell the other most likely). Dynasty is in the same price range as Medallion, but you can use both Omega and Dynasty doors on dynasty boxes (Omega is only really needed if you are going custom)

We have a combo of Dynasty and Omega - some cabinets had to be custom made, therefore Omega, but most are Dynasty. We have both painted (Oyster) and stained (Cherry Nutmeg) finishes and they are beautiful! These are in a basement bar and bath. For our soon to get started kitchen remodel, I would use Omega/Dynasty again in a heartbeat but our designer prefers to work with a local custom cabinet maker...I'm happy to support the local economy! We did get a quote for the kitchen from Omega rep but we were looking at a premium finish (Renaissance-beautiful but too too pricey) so it was quite a bit higher than our other quotes...sorry i don't remember the specifics and everything is getting packed up in prep for demo.

If I remember correctly, there is also a Dynasty II line that is a bit less expensive - i think there are fewer door styles and the center panels are veneer rather than solid wood, but the finish is the same.

I bought the Schuler cabinets from Lowe's, which is Medallion's line as sold by Lowes. I am crazy impressed with the quality of these cabinets (I ordered all-plywood boxes and got free softclose doors and drawers too). The paint finish is gorgeous low sheen, the wood is impeccable, and the construction quality is incredibly solid. They can do custom features including custom sizing (height width depth) in 1/4 inch increments, and can create deluxe finished sides too. I have a bunch of modifications on my cabinets, including the flush toekicks with the decorative cutouts that are currently making my contractor crazy because of the waviness of the floors (you can't just shim those and cover it with toekick molding -- you have to create scribed inserts and paint/finish them to match)

Pricewise I think they're less than Omega, more than Kraftmaid. Mine were 18k with a free sink base and 10% discount. I loved my Lowe's cabinet designer, but I also did my own research on what Schuler/medallion had available, and what would work with my sink selection, since the designer was far more familiar with the Kraftmaid options, and did not understand the type of sink I wanted. Still, she did a great job helping me realize my vision.

I hope this helps. I hope to have pics someday soon, but the place is just such a mess, I don't want to scare anyone off.