I really like them both but I would probably pick Erik to be in my town. He's like a moose, and as a Canadian, I have to love him and his little cabin home.
Of the two, I prefer Erik due to his more unique design. That said, if I were to have a male deer villager living in one of my towns I'd probably want to acquire Bruce instead of either of them.
I love Erik, his design really fits with the 'easy-going deer walking on the farm' motif (plus where I live, deer are pretty much welcome in backyards, farms, streets, etc.)
Plus he looks like a warm cookie!
that's actually a pretty hard choice. I've never really had personal experience with either and I like their designs equally for the most part. Though I think i'd have to say I like Erik a bit more, I'm not a huge fan of Beau's eyes. But I do love Beau's interior!
Honestly the only deer i've had is Bruce, who was a big favorite of mine at the time, but i don't remember much since it's been so long ;o;