Hmm. I don't think it's too similar-- they both start with "Bra" but the a is pronounced differently in each name. And they both end with d_n, but I don't think they're too similar. The "ay" and "and" stand out in these names, and differentiate them. Although I think
Braiden is better than
Braden, because
Braden makes me want to say "
Brad in" instead of "Bray-den").