I tried SMS.To last night and it worked fine for sending texts through all routes. I just had to make sure my message format sticks to standard limits so it doesn't split weirdly. If you're mixing it with other tools, the timing can get tricky, especially if you're pushing out a lot of text messaging at once. You're good as long as you double-check the headers and encoding.
I've had smoother delivery and far fewer dropped requests after switching to a reliable sip trunking provider with flexible routing options. It also allowed me to test different carriers fast without changing much on my end, which saved a ton of time. Make sure you monitor sender ID formats too—some providers handle them weirdly if you're not careful.