The reality of business is that a contract is only worth what you can enforce. SLAs are usually worthless:
1. Unless you are a large customer who accounts for an important amount of their bottom line, probably you have little financial leverage with the vendor.
2. The amount at stake in the SLA is not worth going to court for. It's unenforceable and in fact, the amount is usually meaningless.
Let's say you pay $10,000 per month for your 100% SLA dedicated circuit, and it goes down for an entire month. Let's say the vendor doesn't get around to paying you. Is it worth hiring a lawyer to collect $10K? Is it worth distracting you from your job emotionally and mentally, and consuming many hours of your time? Probably not.
Let's say your circuit is down for 3 hours. Let's say the SLA even pays you 3x what you pay for the service for any downtime (most I've seen just refund the money for that time). Let's see: ($10,000/month) / (720 hrs/month) = $13.89/hour. The SLA pays $41.67/hr of downtime, or $125 for your downtime. Is it even worth figuring out how to apply and filling out the form? No. You have much bigger issues in business, and if you don't ... well, then you have bigger issues.
3. The cost to the vendor is reputation: You tell your peers how much your service sucks, and word gets around. I've had techs take disinterested attitudes toward their poor uptime on our circuit; when I've called the account managers, they can have a very different response - they want me spreading their name around in a different way. That has nothing to do with the SLA.
> Verizon might offer a 100% SLA, but they didn't engineer it to even five nines of availability. That would require redundant equipment and service entrances at his premises along with path diversity end-to-end.
Agreed. There is no substitute for the physical reality of the circuit and service, which you should understand if you are buying it. Putting a shiny SLA on it will have no effect on the outcome.