I have a shared ownership and have for last 8 years.
There are affordable housing schemes with housing associations (which I have) and some with builders.
You own (mortgage) a proportion (mine is 50%) and rent the other half.
It's not always a cheap option. My property is worth £125k and my rent is £181 a month. My mortgage is small because I entered the agreement with equity from previous property.
It's a good idea to check out the staircasing agreement - that's the option to buy a greater share of the property - usually after being in the property for a year.
I pay no building insurance as it's in the rent but I pay the excess on any claim on that insurance.
Selling is the biggest issue with shared ownership - they can be difficult to sell, there have been issues with negative equity, with housing association the buyer has to meet the criteria of the housing assoc and only advertise through them for 6 weeks before going on the open market.
The right to rent the property out is rarely given, even in very genuine exceptional circumstances.
I have an ongoing but minor legal issue with my property which though I own only half the property I have the whole responsibility.
I don't have any regrets but if I could afford to buy the HA out I would but I could not afforded a house without the scheme.
Go in with your eyes open and weigh up each scheme