Hi,
It depends on wath you want and most important wath you want to spend!
If you want to spend as much as you can I would defenitly recommend a JP, but this is a highly competitive engine, and is expensive.
If you wnat to have a relaible engine, and not as expensive, I would go for a Omega (picco).
Those engines are fast and relaible.
But, like I said, make up you're mind and deside wath you want, and how much you can spend!