Well full tilts is an easier structure to learn, main reason is there are no antes to account for.
Competition wise, stars is definitely tougher than full tilt.
The only real differance is that on pokerstars
, players fail to account for the ante, and it's harder to get your effective BB size. However while it may be harder, it's also more profitable, as less players are adjusting to the "adjusted BB size".
Overall full tilt is probably better for newer players. They have a really good rewards/rakeback program there, combine that iwth softer games, it's better for low - mid stakes grinders, who cannot achieve supernova on stars.