Depends on what you need but for SMS bandwidth.com was great. They always knew their shit when we spoke to them. They were just not interested in really small accounts. We quickly realized twilio was worst of the major options and built on Nexmo as alternate (which was fine until vonage bought them and didn't really understand the products or market, maybe it's better under ericsson ownership now, don't know left the space).

When I get text spam it almost always originated from twlio or formerly their subsidiary zipwhip.