"There is not a big difference," he says, when asked to assess the affects of his move from Everton to Upton Park on loan, "though I think there is more of a mix of teams here with more teams that are fighting and more scrappy at times.
"You get teams that are trying to play football as well, but in the Premiership maybe more clubs play on the deck a bit more and that is the difference.
"But the tempo is not a major difference, the speed of the game is quite similar and all the players here are really fit as well."
Niclas' loan spell ends at about the same time Alan Pardew joins so he does not know at this stage if he will stay beyond the first month.
"I am only concentrating on a month at a time and nearer the time we will make a decision; there are a few things that have to be right for all parties, I guess, so we will have to see," he says.
"But I am enjoying the football very much and I hope to get better and better the more chances I get."
Niclas replaced Neil Mellor at half time as the Hammers moved to a four man midfield, and he says:
"I felt a bit sharper fitness wise in the half I just played than my first week here; obviously I didn't play midweek so I am fresh again now and looking forward to hopefully getting a few games in now.
"The whole game was a bit disappointing but Millwall came out as a new team in the second half and they created a fair amount of chances - and probably deserved the point they got.
"Jermain had a good chance late in the first half to get that second goal and we had a few chances even if we didn't create any pressure on them in the second half.
"They could have won it in the end and Jamo made some good saves to keep us in the game so we could have lost it.
"I think we have to forget about this game as quickly as possible and that is the positive in this league - after a disappointing game there is a new game coming up quite quickly.
"So we need to get Millwall out of our minds and start thinking about Crystal Palace."
After three away games on the trot, it is now two successive games at home with a second London derby on the trot on Wednesday - though Niclas reckons it has been easier to play away from home since he joined.
"It seems like we get a little bit more space there maybe to get the ball down and play a little bit more on the break," he says.
"We haven't got a lot of height in the front line or in midfield so if they force us to play long balls as they did on Sunday we will struggle - we need to pass a bit quicker I think."