The Columbia 26 Mk II is not a re-hash of the Coronado 27.
The C26 Mk II has iron ballast (just as an FYI). I owned a Coronado 25 for 2 years as my first boat and there are C26 Mk II's all around me.
First- My little Coronado was built like a tank. I sailed it in 30 kts, and did overnight and beer can races in it. I took 9th out of 15 in the series as my first attempt as racing skipper. A Coronado's primary weakness is the hull/deck joint, which can be repaired.
The Columbias are also tough, and well-built and there is an active Yahoo forum for them, that you might want to check out.
Ok, so they're tough, but how well do they sail? Neither boat is a high performance machine. They don't sail super close to weather, but they're fairly stable. The underwater profile is very low-tech. The rigs are short, and they have short waterlines, so they aren't very quick. They have a low sail area to displacement ratio. These boats are mainly family weekender/short haul cruisers. If you can avoid buying the shoal draft version, you'll do better.
Neither boat can be easily trailered. Both boats will be less expensive to maintain than a 30-35 footer.
Overall, the two boats are very, very similar, and if you had to choose between the two (assuming similar condition and accessories), I'd go with the C26 Mk II because of the active forum and sailing association. You can get lots of help and ideas to make the boat nice, for less money. Even though I owned a Coronado and found it to be a tough little boat, I would still give an edge in quality to Columbia.
Hope that helps.
S/V Old Shoes
1973 Pearson 30 #255