This is probably more detailed a response than was asked for, but there is a lot of confusion among the public on whether H17 is good for the player or good for the house and hopefully this will educate a few lurkers. As a matter of fact, the misconception that H17 is good is so popular that Casino Royale in Vegas proudly proclaims, "BEST RULES ON BLACKJACK - DEALER HITS SOFT 17, DOUBLE AFTER SPLIT, RESPLIT ANY TWO CARDS" in its marquee.
People have this intuition that "pat" hands (17-21) are good, and that's probably the root of the misbelief that H17 is good for the player - dealer has to hit a pat hand, and gets a second chance at busting.
The key to note here is that a hand of 17 - for either the dealer or the player - SUCKS.
(a) Player hard 17 is a terrible hand, with EV's ranging from -0.48 to +0.01 on S17 (-0.27 vs. random dealer card), and -0.52 to -0.01 on H17 (-0.27 vs. random dealer card). As a matter of fact, most people don't realize that hard 17 vs. dealer A is surrender-worthy in H17 games! Player soft 17 is better, but only wins again dealer 3-7, with EV's of -0.20 to +0.26 and an overall EV of -0.04 vs. a random dealer card. It's still an overall loser.
(b) Dealer 17 is a terrible hand as well. If you knew dealer had a 17 every single time, basic strategy (hit everything below 16, stand on 17 and above, split all AA, 22, 33, 66, 77, 88) would give you a whopping +0.29 EV! If dealer were dealt a 7 as an upcard every single time, basic strategy would still give you a +0.10 EV!
17 is a WEAK hand, for the dealer and for the player.
Now being sure of that, it's pretty easy to see why H17 is a bad rule for the player - it allows the dealer to take a weak hand and have a good chance of making a decent hand.
When dealer has soft 17, there's a 45% chance he will end up with an 18-21 (non-crap hands), a 34% chance he will end up with 17 again, and only a 21% chance of busting. You WANT dealer to stand on all 17's.