If you own a house, then a QPRT is a way to 1) live in the house; 2) maintain your mortgage deduction and your $250k capital gains personal residence exemption; 3) give the house to your kids without probate; and 4) have the gift be at a highly reduced rate for tax purposes.
If you own a house worth $500k, you can set up a 15 year QPRT. For 15 years you get to live in the house rent free, then it becomes the property of your kids. The value of the gift is $500k brought backwards 15 years in a present worth calculation - if the interest rate is 8%, then the present worth is $500k / (1.0815) = $500k / 3.17 = $158k. The first $12k of this (per kid) is your yearly gift exemption, the remaining counts against your $2M lifetime exemption. Since the house is already theirs when you die, there's no probate. The interest rate is mandated by the IRS, your accountant knows the current number. It's close to 8%. If your house appreciates at a nominal 4%, then 15 years from now it's worth $500k * 1.0415 = $900k, so you get to transfer a $900k asset with taxes only on $158k.
Of course your kids now have a cost basis of $158k on the house, so they will get hit with massive capital gains when they sell, but we're dead so I figure it's their problem. Currently capital gains is a third of the estate tax rate. If your estate is under $2M, then this is not good tax planning for your kids.
The house may be left after the QPRT term to a normal trust for your kids, in this case you can have a contract with the normal trust specifying that you can continue to live in the house for a specified rent (possibly zero).
If you die before the QPRT term (in this case 15 years) then the QPRT dissolves and the house returns to your estate. Don't die early, it's very stupid.
Since the house is not yours, it's immune to any and all law suits against you. If you get sick and some hospital decides to come after your house, you don't have one. This is very important after you're 65, of course - in the US it's very important to be broke after you're 65. If you find yourself in negotiations with a communist organization, e.g. any private college, then your kid's financial aid calculation does not include the value of the house in any way.
You may be the trustee of the QPRT, in which case you may choose to sell the house (proceeds maintain in the QPRT, the QPRT gets your $250k tax exemption) and buy another house, which is owned by the QPRT. The new house should be of similar value - the QPRT is not supposed to hold much cash. There are laws about what has to happen if there is cash in the QPRT, you have fiduciary duties and must pay yourself (the grantor) an annuity.
Just as for tax purposes you may own two personal residences, you may have up to two QPRTs, if you're married then four. You can leave houses to all sorts of people. Me, for example - keep it in mind.
Remember, poor people don't pay taxes, rich people don't pay taxes, so that makes the rest of us stupid.
The actual law: squid.law.cornell.edu