I build an app for a client a few years back; it's a membership system for a traditional temple. They use the system the like a CRM system, so every detail is within the system, one of the features they request is sending SMS to their member/contacts.
When I built the system a few years ago, I choose to integrate Nexmo instead of Twillo for two reasons. Pricing and Integration. During that time the SMS pricing for Nexmo is quite cheap for Malaysia to compare to Twillo. There is a ready package to integrate Nexmo with Laravel, I need to combine with my code base, and everything will do.
Last night the client suddenly started to mass SMS their member for the first time ( Yes, after three years I build the system ) for announcement purpose. The good thing is everything still working fine except that my credit is not enough so half of the SMS bounce, but the real problem is the cost.
I send 2500 SMS for €80. After converting to local currency which is around 0.15 cent per SMS where local SMS provider can supply approximately 0.06 cent per SMS, for sure the local provider might not be able to provide a useful API interface and much features that Nexmo is offering, but ultimately the cost difference is too much.
I believe Nexmo is a good fit if you having an International Application that sending SMS to users from a different country, but if you just use it for local marketing purpose, getting a local SMS provider should be a better choice.