Web hosting is a subject that divides opinion more fiercely than you might think. When people are arguing about what is most important in a web host, you can prepare for some strongly differing opinions. While there will be many who prefer that the web host has good tech support, and others will prize webspace above all else, a significant number of people will plump for uptime, every time. If your web host provides the right amount of uptime, the tech support won’t be so necessary (and you can always add more webspace later on).
Uptime is, however, essential no matter who you are and what your site is about. You might as well not have a website if it is going to spend more time displaying error messages to the people who want to read it. Most web hosts will promise in the region of 99.9% uptime. None can promise a hundred per cent, as this is an impossible promise, but you will note that the sites that offer 99.99% or 99.999% will be more expensive than those offering the simple 99.9. Nines are costly.
It is worth asking for proof if none is shown, or asking an impartial contact if the hosting company is as reliable as they say they are. It is one thing to lay claim to excellent uptime and quite another to reliably provide it.