Their closest competitor seems to be https://smsprivacy.org https://smsprivacy.org who are similarly anonymity friendly (supporting Tor and cryptocurrency, and

Their closest competitor seems to be https://smsprivacy.org https://smsprivacy.org who are similarly anonymity friendly (supporting Tor and cryptocurrency, and not requiring personal data for signup) and don't filter incoming registration messages. Price: 0.0015 BTC per day(!), which is ~$400 per month at the moment. And they don't support outgoing messages. So Crypton.sh looks like an excellent deal. Wish they didn't require an e-mail address.