I would avoid signing up to BTCery because cloud mining is seldom profitable and the chance that it's a Ponzi scheme is always going to be pretty high.

The only cloud mining service which definitely isn't a scam is HashNest because they're run by Bitmain.  I'm sure that there are several others but the vast majority are either blatant scams or have clever dirty tricks to avoid paying certain people.  Even HashNest probably isn't a good investment - cloud mining seldom could be.

Don't conflate pool mining with cloud mining.  By all means buy your own equipment and join a pool.  Even if they have cheaper running costs than you, you'll be a lot safer and probably earn more profit than cloud mining.  If you have expensive electricity or other major setbacks, it might even be a good idea to steer clear of mining altogether.