I have 3 and like it a lot - I wouldn't change it. They are very close in age - 13 month and 22 month gaps - and in consecutive school years because of how the birthdays fell (dcs 1 and 3 are both very close to the August/September cut off).
They are 10, 12 and 13 now and I'm still enjoying it. My view is that you get more of everything - the good stuff and the harder stuff.
So more love, laughter, fun, support, that sense of being part of a big group - we are a very close family and have always done most stuff together - lots of shared memories, travel, etc.
The harder stuff is mostly practical/expense - it is definitely a lot more expensive (don't kid yourself that you can just hand everything down the line, for example) - it is 3x everything for most stuff, need a big car, especially when they are babies/toddlers in car seats, space in the house is a consideration - we love each other and like being together, but still need to be able to find a quiet space sometimes. School fees/school expenses, travel is much more expensive 3x air fare, often 2 rooms instead of 1, bigger hire car, etc. You have to be proactive in ensuring that they all get the attention they need - this can be hard at times. If someone is quiet /no trouble it doesn't necessarily mean that they don't need you. More guilt associated with this - I have just decided to take an extended period off work as it was taking up too much time and energy (easy enough for me to do this - am lucky) and one my my dc said 'oh good, you'll spend more time with us...'
Bottom line - time, energy and money are stretched further - I feel it is worth it, but others may not.
As an aside, I had them fairly young (youngest was born a month before my 29th birthday) and I think this has probably made a difference to my energy - I think I would struggle a lot more with the baby/toddler years now I'm almost 40. A second point is that we are very comfortable financially - I suspect that this makes a significant difference too.