Samurott at first glance looks pretty mediocre. No secondary Ground/Steel typing like its brothers Swampert/Empoleon, no Dragon Dance like Feraligatr, and no hefty bulk like Blastoise. However, giving him a spot on your team could prove invaluable. His defenses are a respectable 95/85/70 for UU, his Special Attack is fantastic, and his Attack isn't too shabby either. I'll go through some movesets that will bring out the best in him.
Physical Choice:
Samurott @ Choice Band/Scarf
Ability: Torrent
Nature: Jolly/Adamant
EVs: 252ATK/252SPE/4DEF
Moves:
-Razor Shell/Waterfall/Aqua Tail
-Megahorn
-Return
-Aqua Jet/Night Slash
Samurott's decent attack stat becomes wonderful with a Choice Band attached. The choice of move in the first slot is really up to preference. Razor Shell can be used for the Defense drops, Aqua Tail for more power (Although less accuracy), and Waterfall for a balance of power and accuracy. Samurott also gets the scarce but powerful Megahorn to decimate the Grass types that think they can switch in with impunity. You could substitute X-Scissor for it, but the power drop is very significant. Return is there to provide good coverage alongside your choice of Water STAB, and the last slot is mostly filler, but Aqua Jet can be run to score some KOs on weakened opponents that are a bit faster, and Night Slash can be used for Ghosts.
Special Choice:
Samurott @ Choice Specs/Scarf
Ability: Torrent
Nature: Timid/Modest
EVs: 252SpATK/252SPE/4DEF
Moves:
-Hydro Pump/Surf
-Ice Beam
-Hidden Power Grass/Electric/Fire
-Air Slash/Grass Knot
Special Samurott has a few more options than his Physical form. Hydro Pump is ridiculously powerful STAB off of Specs, Surf is powerful as well, but if you opt for the better accuracy, you might miss out on a few key KOs. Ice Beam is there for overall great coverage, as well as your best hit against Altaria and Flygon, as well as grass types. Your choice of Hidden Power depends on what your fourth move will be. If you opt for Air Slash to pummel those Fighting Types, Hidden Power Grass/Electric is recommended. If you opt for Grass Knot to topple those opposing Water types, Hidden Power Fire is the way to go.
Bulky Otter:
Samurott @ Leftovers
Ability: Torrent/Shell Armor (DW Only until release)
Nature: Bold/Modest
EVs: 252HP/252DEF/4SPE
Moves:
-Surf/Scald
-Encore/Taunt
-Ice Beam/Grass Knot
-Grass Knot/Protect/Rest
This set takes advantage of Samurott's DW Ability, Shell Armor. Blocking it from crits so its survivability increases. Unfortunately, until its release, non-DW players will have to settle for Torrent. The moveset is to take advantage of what little support Samurott's movepool offers. Surf can be used for power while Scald can be used for Burn. Encore is to shut down those Swords Dancers and Nasty Plotters that think you're setup fodder. While Ice Beam grants coverage. The last slot however is all dependent on what you prefer. If you would like more coverage, Grass Knot is your best bet to pummel Suicune and Milotic. If you want scouting, Protect is always a great option against Choice users, and Rest is if you want the added bulk. Beware though, it makes Samurott a sitting duck, and it's recommended that you run Aromatherapy/Heal Bell support. For the nature, Bold is for bulk, Modest to hit harder.
Swords Dance Priority:
Samurott@Leftovers/Life Orb
Ability: Torrent
Nature: Adamant/Jolly
EVs: 252ATK/252SPE/4HP
Moves:
-Swords Dance
-Aqua Jet
-Megahorn
-Return
Samurott shares one thing in common with his brother Feraligatr: Swords Dance and Aqua Jet. With lackluster Stats compared to Feraligatr, you'd think that it's just a wannabe set. Megahorn remedies this. Tearing through things that Feraligatr wishes it could. You could opt for Substitute over Megahorn, but then you'd be better off with Feraligatr. The basic strategy here is: Bring in Samurott on a resist, possibly a Scarfed Fire Type or Ice Type, Swords Dance on the switch, and proceed to tear through their team. Life Orb is to bring you into Torrent range faster, making Aqua Jet a 117 Base Power priority move. Or you could run Leftovers for added survivability. Muscle Band/Expert Belt are also options to feign a choice item, and whack them when they think they can send in a counter.
Some Damage Calcs:
Modest Specs Hydro Pump vs. Standard 252HP/0SpDEF Deoxys-D: 61.51%-73.03%-----Guaranteed 2HKO
Modest Specs HP Grass vs. 252HP Suicune: 48.51%-57.43%: 2HKO with Stealth Rock/Spikes
Modest Specs Ice Beam vs. 248HP/252SpDEF Zapdos: 60.57%-71.54% 2HKO
Adamant CB Megahorn vs. 252HP/252DEF Milotic: 51.52%-60.88% 2HKO
Adamant CB Megahorn vs. Standard 252HP/4DEF Deooxys-D: 78.29%-92.11%-----33.33% OHKO with Stealth Rocks, Guaranteed with max Spikes.
Alright guys, those are all the sets I have in mind at the moment. Let me know if you find anything wrong or have anything to add!
Discussion, GO!