It's Mike Smith, and I don't think it's very close. Eliminate Hiller right off the bat, because he will more than likely be sharing the nets next season w/ Fasth.
Between Smith and Miller, lets take a look at some numbers:
2010-13 (3year avg) 5v5 Sv% ( > 5000 minutes played):
Mike Smith -- .9279 (7th overall)
Ryan Miller -- .9258 (12th overall)
Granted, it's not exactly a landslide in Mike Smith's favor, but the numbers indicate that in terms of 5v5 SV% Smith is the preferable option over a large sample size. And while .0021 sv% points may not seem like a whole lot, it can mean the difference between those 2-3 clutch saves over the course of a season -- which may translate to an additional W or two.
Between BUF and PHX, it's pretty easy to see which team is better, or at least which team is better for goaltenders. Under the tutelage of Sean Burke and the defensive first (second, and third) system if Dave Tippett, it's clear goalies really thrive in the Desert (Bryzgalov much?). We saw this in 2011-12 when Smith posted ELITE fantasy numbers and was a top-3 goaltending option in standard leagues. Last season, in a down year while struggling with injuries, Mike Smith still posted a .9243 5v5 Sv% (Miller .9244 almost identical). So, essentially a bad year for Smith is about = to an average year for Miller. This leads me to be incredibly bullish on Mike Smith when given these options.
There is ELITE fantasy upside, his team is a far superior situation for fantasy goalies, and his 3-year averages in 5v5 sv% are top10 in the NHL (7th). All signs point to Mike Smith as your guy here.
Cheers.
MounD - Double Threat FHL (18-19 champs)
10-Team Yahoo daily H2H Dynasty
3C, 3LW, 3RW, 6D, 2G, 7Bn (IR)
G, A, +/-, PPP, SHP, SOG, FW, HIT, BLK // W, Sv, GAA, Sv%, SHO
C: Bergeron, Barkov, Aho, Point, Kadri
LW: Marchand, Landeskog, Hertl, Marchessault
RW: Stamkos, Tarasenko, Laine, Palmieri
D: Carlson, Letang, Dumba, Weber, Pietrangelo, Ristolainen, Byfuglien*
G: Bobrovsky, Holtby, Lehner, Greiss-Varlamov
Farm: Turcotte, Cozens, Denisenko, Newhook // Sandin, Jokiharju, Dobson, K'Andre // Shesterkin