I will start by pointing out that Union at Yonge and Sheppard and Union at Yonge and St. Clair are very different. The one at Yonge and Sheppard feels more like Jack Astors atmosphere wise; the one at St. Clair is more of a small ( and kind of fancy) restaurant with just a couple of TVs. So if you want to have a conversation with whoever you are going out with, go to St. Clair location; if you want to watch a sports event, go to Sheppard location. It's got tons of TVs.
Now, I absolutely have to mention food. It is so much better that at comparable bars. The variety and quality are both 10/10 for me.