I'd say a legit rep or salesman will get you in touch with a senior tech BEFORE
he comes with an offer to you. Most salesmen aren't techs that doesn't mean
they're by default bad people or scammers.
Most important rule is you get what you pay for.
I never take much credit in people praising their provider coz what may
be a good provider for them doesn't have to be a good provider for you.
I'd never go with a new kid on the block kinda provider.....if a provider has
been around for a few years doesn't guarantee you won't have problems but
at least the fact they've been around counts for some reliability even if it's
just the fact they'll probably still be around for another while.
You could check the ip-registry database to see how many ips they have
assigned and if they're a registry member or just using someone else his ip-space. This doesn't tell you anything about the tech knowledge or quality
it does tell you something about the size of a provider.
Check how easy you can reach them for support outside office hours.
ask some network info from your provider, are they multihomed, do they own
control their own routers/network. How's they're peering, if they use BGP
routing ask their AS numbers and check those with the registry to see they're
BGP routing policies.
Do some test transfers at different times and from different locations.
