I used one of those single ring burners with the internal butane bottle all summer - outside a lot. However the gas just does not flow when the temperature falls below about 10C. This 2 burner ring coupled to a propane cylinder (Calor) works really well. Hot tea in just a few moments. The rings are different power outputs, which initially I thought was poor design, but actually for soup and such, you don't want it too hot or it all burns onto the bottom of the pan. For a kettle, you want the big ring - as fast as possible.
So whilst it may seem hard to get excited about a gas ring, if you have ever held a freezing cold can of butane trying to warm it up with you hands so you can get enough gas out to boil a kettle, then you have one of these - it is wonderful. This is well made, and should last. Surprising thing is that it does not have a built in spark to light the gas, nor does it have side wind shields - so for both of those minus 1 star. If you go for a cheaper brand, be careful about power output as some have surprisingly low power output and will take for ever, especially if used outside when it is breezy. All in all I got what I expected, and for the price it is worthwhile.