I was mostly just doing research for a project I am working on and was comparing the pricing models, user interfaces, and any unique features I could find. What I've learned is that the communications market is very sketchy and the knowledge on it is spread all around. Many of the people who have it, aren't typically interested in sharing it.
A lot of the providers out there are just reselling on top of someone else's platform and shortcode, basically throwing in a middle man tax on the text and keyword prices. It would be bad to use a company like that because you want to be the one taking the middle man cut, not them. The real cost for an SMS provider to send a text message is less than a penny, so you can use that as a baseline to figure out where they are making their money.
I don't really have any providers that I will specifically endorse, but remember that text messages are all opt-in and so once you have found a provider, it is almost impossible to switch. I changed over one restaurant, who had 200 or so subscribers, and around 50% didn't re-opt in. The business was not happy. That is why it is so important to pick a good provider. I've got a few customers locked into shitty platforms because I am worried to move them. The SMS Local Supreamcy WSO (that was shared here) is really a white label platform that costs $47 per month (check out the training videos though). I had signed up for it just to play with their platform, because it let you upload it onto your own server. At that time, I had a nightclub I promised a free trial to and so I decided to put them on there as a temporary thing because I didn't think they would stick with it. Long story short, they did stick with it (even though the platform is so ugly and barebones) and now I'm stuck paying that $47 per month, every month. So remember that whomever you choose to go with as your provider, will be a long-term partner.
All SMS companies know that it is difficult to change providers and so many will try to lure you in with a good deal and then get you. Even txt180, who seems like a pretty good company, uses this tactic in their consumer model. They offer a pretty reasonable and cheap entry, with their $17.95 package having 1.8 cent messages. But if you need to buy more, the smallest package has 4 cent messages...Their reseller package has a lot better prices though, that you can easily mark up (1000 msgs/$20=2 cents) and cheap keywords. They appear to make most of their money off of you from the $300 yearly recurring fee. This fee is pretty reasonable compared to a service like Trumpia (who has members here on the forum). The Trumpia platform is relatively nice, but to become a white-label you have to buy a huge text bundle upfront, and the cost is over $3000. There are a few others here on the forum who try to recruit people to join their services, some are Network Marketers or Multi-Level Marketers, who are trying to get you to sign up under them because they receive a commission (iZigg is like that). With those there is the same middle man problem and the lure of trying to hire others down the line.
TL;DR - Pick your provider carefully because you are pretty much stuck with them.
