Recommendations? And do they payout promptly?
... but becareful if you're planning to bet with a huge amount on sportsbet because
once you reach a withdraw amount of 10btc they will ask some information(kyc).
Are there sites that don't ask for KYC and pay big sports wins promptly?
Are they ever hassle free?
I usually use directbet site and their you no need to open an account also to bet, but they do have some limits for each bet. Their limit always worries on match to match, but they also pay promptly and on time. If you want to bet more than the limit they set then you need to send coins from different addresses.
You may get it wrong, you should check their terms about withdrawal. Most bitcoin casinos (sportbetting) reserves the right to ask you KYC verification for withdrawing big amount. Even though it is rarely happened but it is still happening in this bitcoin gambling industry.