I'm going to play devil's advocate here a bit. IMO, from what you've shared, the bikes you're considering are going to be similar regardless of their component level. While Utegra is nicer it isn't so radically different from 105that it renders an otherwise comparable frame or style of bike (e.g., road versus touring) all that different.

What do you want the second bike to do that the Avail doesn't do already? Is it just that you want a bike that fits you a bit better? That's certainly legitimate, but if that's the case, I would worry less about the components (and to some extent, frame material) and more about fit.

If I were looking for a bike to compliment an aluminum frame, I'd look at steel. Assuming the bike fits you, the ride quality may suit you better if and when (if you don't already) do long or multi-day rides.