Why is MF so much more stressful than MM/LMM?

Ignore title, I'm an Associate in a sector-focused UMM here, but have worked with a few MFs on deals during my time in IB.

You're right in the sense that in most cases, those at MFs are more well-equipped to do the job in terms of access to materials. However, what makes it more stressful vs. MM/LMM in most instances are the longer hours, the incremental hours which are spent doing pointless analysis. You also have the fact that it's a returns-based industry and this has been an issue for a lot of the old-school MFs in recent years, so this creates more tensions in certain teams over time.

Fewer promotion opportunities due to lack of space for more VPs, Principals, MDs and co. This can be an issue at the smaller funds too, but it's more prevalent at the larger funds, hence, most at UMMs/MFs move down when it's time to get a title boost. Lack of promotion opportunities create a more tense and political environment, as people will stop at almost nothing to try and get one up on another associate. Office politics happens everywhere, but there's a reason why the likes of TPG, Apollo and KKR are known for having intense cultures, with minimal contact with colleagues other than for the sole purpose of work

With the names listed above now being public firms, an already stressful job (some of the reasons listed above) with the extra scrutiny of shareholders and a general public which hates the whole sector, leads to more stress for seniors to produce good returns for shareholders, which then trickle down to jr. culture

To be honest, think it just depends on the culture of the team and their backgrounds. Worked at a growing LMM place where partners spun out from a MF. Had to deal with everything discussed above for less pay. Place had a ton of turnover. Wouldn't wish it upon my worst enemy. Moved on to greener pastures in the family office space where I don't deal with that nonsense. The last IC memo I did at the PE gig was ~150 pages, now I do ~25 page IC decks.

When one senior partner who is also the ic is on all the deals and or talks everyday re the deal it makes communication super efficient vs having to update ic constantly and make fancy materials all the time 

I’ll add to the above.  Our teams are very lean (one partner, one principal, one associate) and, partially due to the leverage that our resources create, we are expected to manage a larger number of processes at once. As a point of direct comparison, at my prior MM I was expected to “run at” 1 or at most 2 truly live processes at a time, versus today I am leading 4 and what is about to become a 5th. I’m still responsible for every nuance because our CDD advisor or our legal counsel aren’t the ones risking LP dollars and I am in no way shielded by relying on their analyses or viewpoints. Most of our companies have global operations and legal considerations which compel late night and early morning calls with counterparts based in what I’m convinced are intentionally the least convenient time zones. The “cat herding” process management of diligence just gets out of hand sometimes.

Separate from deals are the frequent high level requests from leadership and also across the organization. As examples, just in the last few months I’ve had to prepare materials and “brief” one of our board members on a random emerging market (that we’ve never done business in) because he was meeting a cabinet member there and needed to at least give the impression of being informed, or “boil the ocean” on partnership and coinvestment opportunities for one of our largest LPs (knowing that none of these will actually materialize), or briefing another partner who had an advisory council meeting at the White House, or figuring out the optimal fee structure for a new product we’re launching based on how it will impact our public shareholder reporting. These all have to be prioritized, but so do deals, so it’s a constant internal judgment call of how to prioritize time and how to “manage” the leadership so nobody is either breathing down my neck or disappointed.

All that said - I often work on incredibly interesting stuff and could probably retire now or latest in a few years (late 30s) if I didn’t actually like the work (I do, a lot).