Definetly go by the sirio.
Nova Rossi and Picco are the only serious .21 engine builders. The rest is bollox
JP, Sirio, KHM, R&B, Collari, Paris, MAX, NovaMega, Omega and so on and so on, all use engines based on nova rossi or picco; that is for a reason! these two are simply the best micro engine builders in the world. I own a FC power blablabla .21 it is almost the same as the hyper you are looking at. It is fast and reliable, but it is but a breeze comparred to anything based on a nova rossi or picco. I also own a novamega, a mega, and a RB these all are in a class of their own, extremely fast and powerfull. But in all fairness; if you are not using it on a race track or some sort of competition, dont bother buying one. too expensive and too much maintenance. Maybe it be cool to say to yer friends * hey I own a rossi .21 megaturbohyperboostersuperflowousblabla* but their extra power is only intresting when mere splits of seconds count.
If you are just using it in your backyard or racing on a parkinglot against yor friend, good driving skills will beat them anytime, even with an ofna, hyper, or lousy OS engine, and for only a fraction of the cost. It about fun in the first place!!!
(remember that the .21 class is THe most expensive class for competition engines, and that costs of engines has gone way out of hand. 1/8 gasonroad as a class almost died in europe because of this. A US collum writer once said if you dont have the latest in specialy tuned .21 engines you might as well stay home. It is a serious problem to 1/8 scale racers!)

Look at availebility of spares in your region and what they cost, this is far more important.

Oh, and never believe anything about mentioned HP or RPMs, 99% is bull, and there is no international standard of measuring this. Nothing can be told by these figures.
RB stopped pblising anything about performance figures. Why? Cos they suck? No, they are multiple champions! They know what counts...
Choose an engine for its purpose and you ll be fine...

If you have all the money in the world, look at KHM tuned engines or a RB tuned monster or a MAX by world champ fantini...