I've been using pro ones since December on 3 bikes.
All of them holds air fine... as good as any tube based tires. I didn't need tire jack or lever to put them on for all 3. (HED Ardennes Plus, HED Belgium, Shimano WH-RS81)
I've had numerous "flats" over last 5+ months on them. Close to about 8-10? which 3 of them were a little larger than 1/4" gash. All occasions did seal up using orange sealant just fine. The 3 big gashes did take some time and I learned after first 2 that you just ride with really low air till it REALLY seals up before putting CO2 cartridge in it... or wait till it does seal up nicely. Wasted 2 extra CO2 cartridge that way. I did take them off (using similar method as original poster after first "messy" event) patched the big gashes up and riding it still without much worries.
I believe a pair has about 1800 miles and looking good to me for another 1000 at least(23mm on RS-81). A pair have about 1200 miles on it and looks just fine.(23 Ardennes Plus) A pair (28mm on Belgium) has about 500 miles and looks new.
Just build another Belgium Plus to use with 25mm version... (finally got it)...
Only real con I see with this tire is... soft casing. Seems to get knicks and cuts a little too easy compared Michelin Pro 4 I used to use. But considering the much better comfort, sure grip, and less anxiety of flats... I highly recommend it! Just hoping price does go down a little... as sealant + expensive tire makes it bit pricier than tubed version of similar quality tire. (In my case, sealant seems to be lasting somewhere between 4-6 months)