[heyleise]

There are four daylong tournaments and ACBL Daylong (MP) 1 always seems to have the most number of players ... is there a difference between the four sessions based on skill level?

[hrothgar]

heyleise, on 2021-January-01, 08:29, said:

There are four daylong tournaments and ACBL Daylong (MP) 1 always seems to have the most number of players ... is there a difference between the four sessions based on skill level?

Not that I am aware of

I think that people naturally start with #1

[pilowsky]

The same is true of the BBO daylongs. Over time, I think people have realised that BBO MP number 1 is the biggest, so they gravitate towards it. In the BBO DL No.1 each hand is played against 30-33 players (roughly).

This means that you compare your skill level to the largest available pool of players on each hand.
BBOMP1 is also NOT stratified. Players are ranked according to their percentage score (1000+ participants every day). A slightly less than 50% of them are awarded the masterpoints on a logarithmic scale until exhausted (the points, not the participants).
This means that the winner of a typical BBOMP1 can gain more than 12 masterpoints in one hit.
I believe that this means that this tournament can be considered the world championship of (robot) Bridge every day. Some would argue that robot bridge is not the same as so-called 'real Bridge'; this is true(ish). There are IMHO certainly enough similarities, so that good players in one format tend to be good at other formats.

The ACBL tournaments differ in at least two critical respects. The maximum number of masterpoints that you can gain is limited to about 1.0 because everyone is ranked in separate pools and then stratified into 3 groups: A, B and C. This means two things.
First, a player who is not a world expert has a chance of acquiring masterpoints - but not as many.
Second, the tournament entry fee is USD1.35 compared to USD0.39.

Personally, I don't aspire to own masterpoints of any particular shape colour or nationality. I like to compete in the toughest field available because then the best bidding and play are accurately rewarded (most of the time).
Of course, given the current quality of my bidding and play, the rewards are rather infrequent, but that's Bridge.
Doubtless, others have different views depending on their outlook on life.

You can also play with a partner in the BBODL1 (not, of course at the same table). Just add your percentages together at the end and see how often you crack a target percentage. We try to aim for (player1+player2=) 100%. Winning is hard enough on your own.