Cannot get GV to stay connected in any reliable manner so exploring other vendors. Note: This line is rarely used for any calls - mostly want it for 911 and as line for our alarm service to use when alarm is triggered.
Any low cost, reliable companies to recommend based on firsthand experience?
Well, you're going to get a bunch of opinions here.
If you want a reliable provider with E911 service and low, per-minute calling rates, many of us use Callcentric.
For example, see their rate chart below. Their E911 service is $1.50/month, but they now have a "seldom used" plan, for only $1.95/month, that includes E911. So, it's only 45 cents a month more, for 120 minutes per month of outbound calling.
Oh, and I should also point out: there is nothing inherent to Google Voice that would cause serious connection issues. You may find that you have the same problem with a SIP VoIP ITSP, but the good news is that they're mostly no-contract, so you can just cancel it if it doesn't perform well for you.