The cars were sold with 4 cylinder engines, although there were variants such as the MGC and MGB GT V8, which got 6 cylinder and 8 cylinder engines, respectively. As one might imagine, a V8 engine in these cars would turn it into an fast racer against just about anything of its time.
These cars were originally all convertibles, but a coupe version was sold starting in 1965. These coupes were also given the GT name.
These cars all had two doors and 2 full size front seats and for the most part no rear seats. A small rear seat was an extremely rare option during some years. If you can find one of those for a decent price, I suggest you buy it.
These cars had good acceleration, but they were best when going around corners. They have better cornering than a modern day Mustang, which is saying a lot for American automotive innovation in the past 40 years.
These cars were quite small, so one would imagine that they would be unsafe in a collision. That's not necessarily the case, as the MGB was the first car to feature a crumple zone to protect the driver and passenger in a crash under 30 miles per hour.
As I mentioned before, these cars are quite collectible. There are hundreds of clubs and groups that celebrate these small British sports cars. If you are looking to buy or sell one, I suggest using eBay to avoid the overhead of a go-between dealer. eBay is also a great source of parts, and there are literally thousands of listings for parts for these neat old sports cars.