I've got the Curado K and the Concept A. Both are great reels, at least in freshwater since I haven't used them in salt. They're both saltwater approved, but I wouldn't know from experience.
I feel like the concept a is a reel that can take a beating, be neglected, and work just fine. I use it with heavy braid and flip into heavy cover knowing that if I set the hook, that 22 lb drag isn't going to slip. A heavy flipping hook will bend out before it slips. Comparing cast/retrieve between the two, the curado is much smoother and casts farther. The curado has little to no play in the handle or spool, the concept a does. You'll definitely hear some crunching if you get a few grains of sand in the curado though.
Both are awesome, both have strengths and weaknesses depending upon the application. I say get both.
Curado: Sports car
Concept A: 4x4 pickup