it takes about 15+minutes (if something doesnt goes wrong) just to rent a miner!
This is just retarded...
+ it takes 5-10minutes just to start mining, you should start counting time from the moment it actually does start mining! otherwise its just money down the drain if you are working on very slim margins!
Why do you believe the counter starts the moment you click the "Confirm" button? It appears to me that the counter starts as soon as the payment has received 1 confirmation.
At that point it takes 1 or 5 minutes to start mining, depending on if they are using sgminer or cgminer.
I've had 20 transactions, some to rent out and some to rent other rigs, all without issue.