What you see isn't always what you get.
Other lenders show you an exceptional rate, but once you apply for their loss leader rate you find out it isn't available.

They markup your rate based on your down payment.
If you put less than 30% down other lenders may increase your rate.

They only offer their best rate to the highest credit scores.
Most other lenders will increase your rate if your credit score isn't above 740.

They bump your rate up based on your income.
First they calculate your debt to income ratio. If your income isn't high enough, they increase your rate.

They increase your rate to earn a bigger commission.
You've probably never heard of "yield spread premium," but other lenders have. If they can bump up your rate, or sell you a higher rate, they receive a bigger commission.

Will they increase your rate if you're closing beyond 30 days?
Other lenders increase your rate if you're closing beyond 30 days out. This one trips up many innocent buyers.

They increase your rate if your loan is too large or too small.
This one's too big. This one's too small. But which one is just right? Only they know. To them a small mortgage isn't profitable enough. A loan over $360,000 is a high risk. Both are just excuses to increase your rate.

They sell your mortgage.
Most other lenders sell the servicing of your mortgage, so you never know who you'll end up dealing with. Third Federal has never sold the servicing of a single mortgage.