Well, personally I would go with Sammy (Samurott!) lol, but you can decide by the stats.
Jellicent is better by 5 points in HP [ 100>95 ]
Samurott is better by 40 in attack [ 60>100 ]
Samurott is better by 25 in defence [ 70>85 ]
Samurott ALSO is better in sp. attack by 23 [ 85>108 ]
Jellicent is better in sp. defence by 35 [ 105>70 ]
Samurott is better in speed by 10. [ 60>70 ]
(The Higher number is the Pokemon with the higher stat!)
With the movepools: Samurott has a wider movepool, with great moves such as mega horn, Dragon tail, Ariel ace and a few more, especially in egg moves.
HOPE I HELPED! ^_^
SAM - U - ROTT! (no offence samurott)