I've found most of the Evolution engines to be very reliable ( except the discontinued NX 1.00 ), once you get past the limiters.

They have a couple of quirks, as do most engines ( including O.S. engines, e.g. the need for that thrust washer and woodruff key), and once you understand those quirks they run quite well...

e.g. in Evolution's case

- Limiters on the Needles
- Grey Goo during break-in