Anyone use any SMS services like Nexmo or Twilio?
Nexmo seems to be the cheapest, but I had trouble with their service not leaving an answerphone message - that was a few months ago so maybe things have changed. Just wondered if anyone has used anything similar and how you got on with it?
I use Twilio. It’s easy peasy.
It’s the most expensive too. What do you use it for? Phone number verifications?
This one looks cheap 
https://www.sinch.com/pricing/verification/
If you don’t plan on having many users and you have unlimited free emails then you can simply email SMS to the phone you desire. To do this you need to know the email address syntax for every cell provider and mass email the specific-phone@cell-provider-service.ext . Since the number will only be registered with only one email provider you can send it to the several hundred providers and the one owning the number will get it. In theory this should be free. But rate limits, expenses, and spam blocking will become an issue. The only work around with this is to know the user’s provider by a) asking them for it, or b) paying for it. If you’re going to pay for it you might as well use Twilio.
I use Twilio for everything. ATM I have it designed with personal messaging, account registration, friend referral, and phone verification. I have many other features in the works.
I looked at email-to-sms, but felt it was too limited (not every provider supports it) and too much hassle.
Your project sounds like it’s making good use of it 
Looking at the prices again, I am not sure this is the case - Twilio seems to quote fixed prices, whereas Nexmo says ‘from…’.
What I might do is cycle a thousand verified numbers for each of them, and then see which one works out cheaper after a year or so.