I do very large, studs-out type renovations. I've tried management a variety of ways. We've used an external project manager overseen by an internal liaison. That didn't work so well, as we had multiplication of efforts and just too much cost associated with the whole thing.
Then we tried an external GC. The GC had a foreman who did the day-to-day. That worked really well, but also cost mega bucks. The biggest advantage was that the GC dealt with the permit requirements and the whole thing went really seamlessly.
So finally what I have ended up with is that I act as the project manager with a foreman (who is also my lead carpenter) on the ground handling day-to-day business with the subcontractors.
I outsource someone else's GC license in order to get permits pulled, although I'm about on the brink of getting my own GC license so I can pull permits directly.
What we ultimately learned was that there's really 2 layers of management needed in a large rehab.
You need a foreman, period. Someone must be on-task to watch the day-to-day proceedings, and he needs to be there all the time. He also needs to be skilled and working. This person will probably be the highest paid individual on your on-the-ground construction team.
(In business terms, this is the tactical manager)
Beyond that, you need someone to manage the project at a strategic level. Watching the tactical manager is part of that person's job.
He needs to be the one to account for all receipts for every nail, board, and tile that goes into the job.
This is the guy that needs to make payroll every week. Pay the subcontractors directly. Manage the t-accounts and ledger on a real-time basis to make sure that everything is going correctly.
Also make trips to the job site at least a 3 times a week to drop in and ensure that everything is on schedule and looks correct, and is proceeding according to the time schedule and the physical layout specified.
In other words, the guy who sees beyond the day-to-day tactical execution of the project and ensures that strategically, everything is going smoothly. This is really not an easy job. You need someone who has a very strong ability to think like an accountant but who is also able to effectively audit what's going on with your carpentry crew, sheetrock, flooring, etc. etc. etc. ad naseum.
In smaller jobs, both of these positions may not really be needed. If all you're doing is painting walls, installing flooring, and new countertops, then you may nott really need all that management... or those guys may not be doing as much as they would otherwise be doing.
However, when you cross over into really large projects where you've got multiple different trades in and out, lots and lots of material purchasing going on, a dozen different checks flying around at any given time, and above all else a house plan that needs to be translated into bricks and sticks correctly THE FIRST TIME, then having that much management becomes, IMO, essential.
So to answer your question, I outsource my foreman and act as my own strategic manager. It took a long time for me to be competent to do the job, but ultimately it's the only way I can satisfy my need for control while not having to be at the job site 100% of the time.