In some ways because any discussion of Monty will always bring either Patton or Rommel into it it reminds me of discussions I have seen on other boards about piston aircraft engines in service during WWII. Napier and Bristol afficionados will extol the virtue of the sleeve valve due to its inherently more efficent specific consumption (the ratio of HP per hour vs the weight of fuel burned) over the poppet valve designs of the rest of the manufacturers. On the poppet valve side others will labor on about the increased manhours in manufacture and the greater demands that the sleeve valve placed on its designers and builders due to the required accuracy in machining and grinding opperations during the manufacturing process. Along with the increased oil consumption of the sleeve valve vs the poppet designs (as a side discussion the poppet side of the arguement will always side off towards radial air cooled vs inline water cooled).