1. borrow up to 1/2 of acct bal;
2. interest rate about 4-4.5%; but interest is actually paid to yourself;
3. not borrowed in the last 1 year;
4. payment plan can be 5 years amortized.
there is NO penalty. you do NOT withdraw your balance. you borrow against it.
as mentioned by others, 6 months or 1 year later, you can get a HELOC for the property with zero closing cost based on the marked to market value of the property to cash out. you can pay back the 401k loan if you like at that stage.
just my 2c.