I'm getting used to it. There are times when I just wear the Hamilton and prefer using my Xperia X Compact over the iPhone. - then I'll leave the AW at home; other times I'll wear both while I'm carrying the iPhone.I haven't seen anyone wearing a mechanical Watch and Apple Watch at the same time, but it seems quite a few forum members appear wear both. Personally for me, that's a bit much.
I've not yet carried both phones with me; having 2 phones and 2 watches at once would be a bit much.