I think the 2 companies are legit and we can make money with them and I don't think it's a ponzi scheme.

But two aspects disturbs me a bit about cloud mining :

1/ --------------
The client doesn't have control over the mining pools where the hashing power will go. It's controlled by the cloud provider.
Let's say I've created my own mining pool, and want to send all my rented hashing power there, then this is not a possible
way for cloud mining. You can't lead the mining where you want...
So you don't know exactly how many coins were really mined for you : 100 coins, 150 coins ? only the provider knows...
You are forced to blindly trust the daily earnings shown to you, without knowing exactly what happened during the hashing day...
Nothing can stop a provider to keep some coins apart. You will never know that.

2/ -------------
Why a provider would rent its huge hashing power when the company can mine itself and make money without us...
I would say the paid money would be to buy extra hardware to let you mine. Hmm, I suppose that when you buy hashing power, your mining starts instantly, isn't it?
So they have the hardware at hand already...
Also, won't it be more profitable to let all their mining hardware run altogether instead of waiting a contract to
be paid before letting the hardware start mining? I'm sure they buy extra hardware to handle more hashing power, but I suppose that every machine is used to mine ,
even with or without a contracts linked to running machines.

Cloud mining has its potential, but I would be more reassured when a cloud mining service will let us
set where the hashing power will really go... I would like to see, live, how many coins are mined with the power I would pay.
The only way for that would be to let us tell on which mining pools we want to use the hashing power and by using our own mining credentials on pools.