At some airports, the pre-check lines are longer than the regular lines, but they do still move faster than the regular lines. This has happened to me frequently in the Washington DC area, and also less often at my home airport of San Diego. Military and civilian DoD employees can get pre-check just by using the number on the back of their CAC (federal ID card) as a known traveler number, so in cities with a lot of federal employees and military personnel, you will see longer pre-check lines. I've groaned when getting in the longer lines, but have still beat colleagues who got in the shorter lines without pre-check.
If you do get pre-check, you should still pack your liquids in a baggie that you can easily remove from your carry-on. Sometimes pre-check lanes are closed and there are also airports and terminals that don't have a separate pre-check line for some of their gates. E.g. in San Diego, for a flight that leaves out of gates 1 or 2, there's only one security line. If you have pre-check you get a pink card that means you don't have to take off shoes or jacket, but you still have to remove the liquids and laptop from your carry-ons because they're all going through the same x-ray as the non-precheck luggage.
As someone else pointed out, a good way to get pre-check is to see if any of your credit cards offer it or global entry as a benefit.
If you do get pre-check, you should still pack your liquids in a baggie that you can easily remove from your carry-on. Sometimes pre-check lanes are closed and there are also airports and terminals that don't have a separate pre-check line for some of their gates. E.g. in San Diego, for a flight that leaves out of gates 1 or 2, there's only one security line. If you have pre-check you get a pink card that means you don't have to take off shoes or jacket, but you still have to remove the liquids and laptop from your carry-ons because they're all going through the same x-ray as the non-precheck luggage.
As someone else pointed out, a good way to get pre-check is to see if any of your credit cards offer it or global entry as a benefit.