I have a rocket here, it is fine for what it is, there are a few issues though
There are a couple of different versions of boiler but they all only hold 60mls of water so short run times.
The burners need cleaning often and the plastic gas tanks split but after market metal ones are available.
The engine is listed as 3 1/2 inch but it is actually 3 mm less so will not run on standard track, it falls in between especially on the bends if gauge widening is present.
The plastic track for the rocket is hard to find and expensive and is too small for standard 3 1/2 inch trains.
Hope this helps.
Cheers Dave