I have not myself, but I know of many people who have used Rajiv Khanna and some other "long distance" lawyers (like Jose Latour of usavisanews.com). They have all been very happy with the services they got. Infact, my lawyer is local, but I have hardly met him myself. Our communication has been over email, phone or fedex. From what I hear, and experienced (when i asked a few questions to Rajiv Khanna - utilizing his free services) he is very responsive. Probably more than your local lawyer would be.....
Bottomline - if I were to choose an immigratioin lawyer on my own (i hope i wouldn't need to), Rajiv Khanna and Jose Latour would be at the top of my list.