It's very easy the thing you need to keep in mind is that the most important piece of equipment is a RELIABLE thermostat, the one you linked does not even have that and I would not trust the internal T-Stat with MY eggs. I would trust a DIY incubator over one of those any day.
Now if you really want a professionally manufactured incubator (which will get pricey for a RELIABLE one) there are some Hot Box (From C-Cerpents), Nature Spirits, and BoaMaster