Lasers have been around for absolutely ages in the UK. The proprietor, Niel Tidy, used to be a constant contributor to the modelling magazines with "build it yourself" articles for small diesels and the like. He then began producing 4 stroke engines in about 1986 with CNC machined parts, all from billet. The key feature of the Lasers were high performance due to the intake configuration and the ability to perform well with straight (non-nitro) fuel. Modern lasers use advanced cylinder lining techniques with some aesthetic changes to the machining. the intake and exhaust configurations are unusual and allow some re-orientation of the control link and needle directions.
I have one and it starts a dream (unlike my Enya that needs a starter). I prime by placing my finger over the carb and drawing fuel up by flicking the prop. I then apply a remote glow source and twist the spinner backwards against compression. The engine usually starts immediately, first time and burbles away very quietly. Pick-up is very rapid, I don't think a pump would assist at all and the power of the Laser 90 Mk 1 is excellent. I have run it off straight 20% castor, but I prefer 10% nitro with 18% Klotz Techniplate. After sales service is excellent with spares easily obtained direct from laser or carb spares from Irvine or Super Tigre.
Although Saito GK's look pretty, I think the Lasers are just as nice in a different way and are better looking and better performing than stock Saitos.
RCV engines are a completely different company. Their trick is to use a rotating cylinder liner as the intake and exhaust valve. (Hence Rotary Cylinder Valve). They have engines powering drone aircraft (Predator I think) because the engine is economical and less prone to failure because of the simplicity of the valve arrangement. One aspect of their performance is that the propellor turns at half the rate a conventional 4 stroke would for the same number of cylinder firings. This tends to make them suitable for larger props or multi-blades. the sound is different to a conventional 4 stroke. The in-line versions need a special starter adaptor. I haven't got one of the mor conventional lookig types, so I can't comment on how you start them.