Always the scare tactics...:neutral: These SAME scare tactics were employed back when roller furling head sails first hit the market. Today there are folks like John Harries who sails his vessel in high latitudes with over 100k nm on his roller furlers. If you had listened to the same rhetoric back in the 70's these would have failed him the minute he left the dock.
We owned a boat with in-mast furler. We NEVER, EVER had even a hint of a jam and NEVER EVER had a single problem. We LOVED it. We also SAILED MORE !!!!!!!!!!!
WE SAILED MORE...
Think about that......

In little to no wind we could deploy the main at the hint of a puff and be sailing in about 12 seconds. If the wind again died we'd put it away in about 12 seconds... With our full batten main we just opt to keep the iron genny going until we have enough wind to keep the main up.
When single handing, as I do multiple times per week, the furling main was a god send. As it is now I often sail under the 150% genny only because of the extra time involved in depolying the main and putting it away. I can be on the boat and off the mooring sailing in under 3 minutes by sailing with just the head sail. If I add the full batten main to that equation I lose an extra 20-25 minutes of actual SAILING time... With the furling main that was never an issue and my time spent for hour or two "sneak off sails" was maximized..
We had a wing keel Catalina 310, with in-mast, and a fixed three blade prop. We regularly used to dust our sister ship who had a fin, full batten main and a folding prop. If you focus on how YOU sail, not the loss of roach or other "excuses" you will become a better sailor.... If you consistently blame your speed under sail on things like props, sails, in-mast furling or other things you'll never become a better sailor.
Even Dodge Morgan had an in-mast furler on his private sailboat, a 54' Little Harbor. This is a guy who set the solo round the world record and who then chose in-mast furling for his personal sailboat...
On our current boat we now have a full batten main (actually a 2+2) but I would go back to a furling main in 2 seconds. Personally I would prefer a boom furler, due to the ability to have battens, but would not be opposed to another boat with an in-mast main. It was one of the best features of our Catalina 310....
Like anything when used PROPERLY they are highly reliable. I have one customer with a 30 year old Hood system that has never had a single hiccup. He loves it.
All I am saying is that if you find a mast with the right section and length for your boat don't not buy it if it is in-mast. They work well and have many benefits except of course to those who've never used them....