I haven't yet, but I may.

I was quite familiar with them a few years ago because I've been interested in FIRE since long before the Roth conversion ladder became well known as a method.

The math is easy, although people will say that it is hard. For the minimum distribution method, you take your year end account balance and divide it by a number that you look up in an IRS table - you do this for each year. For the other two methods (amortization and annuity), you plug in your account balance, age, and an interest rate into a web calculator and out pops a number - you do the calculation once and then just take that amount every year.

The amount you can withdraw depends on a couple of things. First, your age - the older you are, the more you can take out on a percentage basis. Second, the method you use - the minimum distribution amount typically starts out lower than the other two, but grows over time; the other two methods it's typically a larger amount but stays the same over the period of the SEPP. Third, the interest rate. Higher interest rates mean you can take out more; currently we're in a relatively low interest rate environment so relatively speaking the amount you can take out is low.

I will say that for me, using the amortization method and 120% of the mid-term AFR for November and my age of 50, I could pull 4% of the account balance this year. So for my purposes, it's a viable method. The thing I keep in mind is that it is required to continue for 5 years or until age 59.5, whichever is later, so I would only do a relatively small one, because I then lock myself into that minimum income for the next 10 years.

I haven't done it yet so I haven't been audited. Personally I wouldn't worry about an audit as long as I had either done the calculations myself, had them done by someone I trust who is a CPA, or gotten the same answers from multiple reliable-seeming websites. And, of course, if I used a standard version of one of the three IRS-approved methods. (You can use other methods, but if you do the recommendation is to get a PLR.)

Currently I don't need to start one either, but I think I may start one in a few years that covers maybe 25% of my annual spending needs. The tradeoff for me is the size of my tax torpedo versus preserving my taxable account longer.

HTH.