Look, I'm sure they're great guys, and I'm not going to dissuade you from working with anyone.
That would be inappropriate.
Their site looks pretty. The animation on the home page is damn cool. Wish I'd thought of it.
If pretty is the only thing that's important to you, and you want to go that route, go for it.
But if you do, you're buying a site from someone with a MOZ rank of 10 on their own site, 43 twitter followers, and only 160 likes on their Facebook page. Nothing against them, but those are hobbyist or intern level stats. They're also using long keyword meta tags, which tells you that their knowledge of SEO is years out of date.
Why should you have to think of support as a separate line item on a web project? You're paying them for a service. If it's broken or there is an issue, they should fix it.
Like SEO and the many other things you pay for when you buy a site, it should be part of the package. If they're not including these things, they're knowingly selling you something that doesn't have all the pieces you need.
Nobody's going to get you into a situation that doesn't make sense for them economically.
When it sounds too good to be true, there will be strings of one sort or another, every time.
It's not uncommon for the extremely cheap services to be on par with or notably more expensive than the most expensive ones.
You're better off shooting for the mid-range.
At least you'll get honest bids that way.
That's all I'm sayin'.