Hi Martin,
I never had one, but many did, they were popular. I remember looking and watching, if that makes sense, being totally taken in by it all. The smell of the fuel has always remained with me.
As to how good they were is difficult, they ran well in that they delivered power well and in quite a controlled manner, which alot did not do at that time, but they were not exessivly powerfull by todays standards. I would describe them as a good slogger, but they looked good!!
The other thing was starting them, start on the front cylinder and then bring the back cylinder in, that was the way. with a leather boot lace. I was using little DC engines as the electric engines, mainly Taycol, were also lacking power by todays standards, they were big and heavy, they also needed big batteries, again which were pretty disapointing by today's offerings
Hope that helps
Mark