Hey Stan, I've had the Sena SMH10, 20S, and now I'm currently using the 30K. Most in our riding group (same guys for more than 10 years) are all using the 30K. We've been doing multi-day trips over the past few years and it's pretty awesome.
Don't get the SMH10, it's the older technology. At the very least, get the 20S though I would highly recommend the 30K. The 30K can be completely set up through a phone app instead of using a PC or MAC. If you intend to do any trips with others, the range is much farther than the SMH10. The 20S and 30K are able to be paired through a phone app. The 30K can be paired with non-Sena units which is a nice upgrade.
Not that it matters in your situation but Sena was smart enough to retain the 20S helmet mount when they made the 30K. This means I didn't have to get extra mounts for different helmets.
If you have any questions, PM me.