The two clubs are a "pretty completely opposite", Ashton told BBC Three Counties Radio.
"It's a relaxed place. I'm not saying Northampton wasn't but it was quite full on a lot of the time," he said.
"They trust you to do your own thing, the lads in general are quite a welcoming bunch and I've had no problem speaking to anyone or being around anyone. I'm enjoying it so far."
So determined was Ashton to make a positive start at his new club, he reported for pre-season training a week before most of the squad.
"One of the reasons I came here was to help my rugby, to freshen it up and push myself again.
Ashton scores four tries for England against Italy
"Coming here, I've got to start again with it all, I've got to impress and I've got to get myself in the team.
"They've got good wingers here who can play instead of me any time so I'm always going to challenge myself," said Ashton, who began his career in rugby league with Wigan before switching codes and who has scored 15 tries in 23 appearances for England.
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