I've run all the major oar manufacturers from wood to composite over the years. I like lightly counterbalanced sawyers mxf's at this point. I have a 15' boat 72" wide frame and run 10'ers, which work great. They have 1.5 lbs of lead in the handle but agree that balance will depend on set up.
I have had ALOT of problems with cataract shafts shedding glass and none with Sawyer. My stuff is on the water 40+ days a year now that I have kids and 100+ BC. I've seen both cat and sawyer finishes degrade but there is a difference - sawyer wraps their glass in cloth fabric so when the finish degrades it DOES NOT shed glass - that is speaking from first had experience. Between this and the removable wood handles that they use, I buy sawyers.
I've seen that cat makes a new removable handle with which you can interchange from counterweighted or not but I have no experience with them. I like the feel of the wood and I just made little lead ingots that I screw into the inside end of the wood handle - works great. At 1.5lbs of counterbalance my oars float flat - I chased one down the upper Gallatin this year for over an hour and it layed flat as pancake the whole time.
FWIW I do not want my oars balanced - much like yesimpirate, I just want most of the "hold up" weight removed. I still want the blades to fall in the water when I'm not holding them. My original pair of sawyers had 4 lbs of steel in the handle which was way to much for dynelite blades. It might have been appropriate for wood blades but not for the carbon ones. I would not personally buy pre counterbalanced oars. I'd figure out what works best by wrapping ankle weights or lead (like this: Cabela's Bullet Weights Hollow-Core Lead 5-lb. Roll : Cabela's
) around the handle until you get the weight right. Then remove the handle and attach inside, reseal with silicone and be happy.
As for blades I'd get sawyer duramax or dynelites for sure. Carlisle's suck, plain and simple. I broke one or two a year before I switched and now I've been running the same d-lites for 8 years. I have duramax for spares but haven't spent much time using them. I do have several friends thought that have used them for years (also after switching from Carlisle) and have had not problems. They are almost the same price as carlise's and a no brainer for me if you're not going big. I have no opinion on cat's blades - I tried magnums once and one delamed right away. I assume it was a fluke but that's when I went to d-lites and have no reason to go back to plastic.