Vortex is a fine brand. They have great optics and a great warranty. Their Diamondback line is solid and affordable. If you can afford to spring for the Razor line, you will not be disappointed.
Everyone will have their preferred brand. I would recommend reading as many reviews as possible and feel out what the good brands are. Some qualities I consider important in a spotting scope (besides optical clarity) are field of view and ease of focus. Some scopes will come with one focus wheel and others will come with two (one for large adjustments and the second for fine tuning). It all comes down to what you consider easiest to use.
You will also want to consider a good tripod. A light breeze when you are at 60x magnification can make for a shaky image on a weak tripod.
I hope that is helpful. Best of luck in your search!