Jesus recited the Lord's Prayer when asked how to pray; no mention of what he did with his hands, so I suppose it doesn't matter.

Personally, I find holding hands very distracting because of the physical sensations: colder, sweaty, grip strength, etc....  If you're praying - and I feel this way also about singing the responses rather than reciting them - you should not be distracted.

I love the one-on-one feel of me and God in Church.  I am as comfortable in an empty Church (maybe more so) as I am in a packed Church.  I'll catch up with you after mass, right now I'm engaging with God.