Yes, I have, and have lived in one for 10 years. That Private Eye article sums it up really. My service charge started off at £69 pm and is now at around £300 pm. My flat is currently on the market (both shared ownership market and open market as 100% ownership) and whoever it sells with, I will be responsible for paying the commission fees on 100% of the property, despite only owning 30%, which will eat into a lot of the equity. I also had to pay a fortune for a valuation by a surveyor chosen by the housing association, which only lasts three months and is just about to expire. And, of course, I'm responsible for 100% of the cost of anything that goes wrong.
My rent goes up according to RPI, so this year it has gone up by just shy of 10%, which has been hard on top of the service charge increases.
We've had a lot of problems with water ingress/leaks over the years due to building defects, and the housing association has done fuck all about it. It shit and a scam. But what can you do? I couldn't actually afford private rent these days, and I can't afford to buy on the open market, so I'm left with no other option but to play the game.
Service charges in SO houses are cheaper and not likely to increase the way they do in flats as I understand it, so there's that. Clarion are well known for being crap but then most of them are. Is it a brand new house or a resale? You need to check which style of SO you'd be under as the new style SO is a bit different.
Most people who do SO do it because they have no other option. If you have another option, don't do it.