sounds like a advertisement for Monero or Dash to me
if an asshole service provider disses you because of blockchain analysis then BTC has got a real problem
NO FUNGIBILITY!!!!!!!!!
They are no more than "builtin mixing services" but mix the coins to a lesser degree, since any good oldschool mixer hands you over totally unrelated BTCs. The exchanger trick cuts of some chunk on fees and there's that volatility danger.
Something completely draw me away from using Shapeshift, cant remember if this has been lack of an .onion adress, to high fees or to much javascript in their frontend. Maybe everything.