I think if you're going to reshell a universal you need to make sure it's a sound signature you really like. TF10 is the perfect candidate imho because it sounds great, but usually the fit for most people it terrible. I was one of the lucky people who got in on the Amazon deal for $95. I figure with impressions, the TF10 cost, reshelling and cable I spent $260, which helped me decide if I want to go up higher on the custom line. The drawback would be if you don't like your reshell and your cost was about the same if you wanted to sell, you'd probably only be able to get $100 or so out of it, and only be able to sell to someone who wanted to reshell.
Having said all that I love the TF10 and reshelling was definately worth it. I do think that when it dies, I'll go higher up the line (JH16 or Miracle). I might even do this anyway, but definately going to keep the TF10 custom, selling it for $100-$120 seems like a waste.