You judge the whole Splinter Cell series experience based onplaying Splinter Cell: Double Agent. One blemish in the strong Splinter Cell series. Imagine if we judged the entire MGS series based on the abomination that was MGS 2. MGS 2 with Raiden as the lead character instead of Snake and an extremely confusing plot. It would not be fair. Lots of spin off games from MGS main series that have had mixed reviews.
One average game in the series does not make the whole series a failure.
From a sales persepective MGS sells more than Splinter Cell series. Splinter Cell games have more realistic stealth game play than MGS games. The reviews of both series are both rated highly in the wide gaming community. MGS has a much bigger fan base than Splinter Cell.
Splinter Cell: Conviction looks much better than MGS 4: Guns of the Patriots based on those screen shots. I can not wait for Conviction to come out in April this year. Conviction releases almost two years after MGS 4- a huge advantage in regards to graphics improve over time.
Sam Fisher or Snake? Both guys are real bad asses. I like them both, but Sam is the man.