The keyless works quite well and as mentioned by a previous poster you will have plenty of warning before the batteries die on you.
The lock comes with two codes, so you can have one for you and one for the cleaning lady if you like.
If you're buying it for high security, then forget it. Most thieves can get past any outside door lock regardless of the style. Get an alarm or a big dog

Worried about someone getting the code? Just stand in front of the door when you enter the code - or get new neighbours!!
The beauty of this lock is the convenience - like when you go out for a walk or a bike ride or just to take the dog for a walk.. you don't need the keys. Plus, working around the house you can walk out the front door, push a button and it's locked.. cut your grass.. then enter a code and you're back in.
Finally, prices range in the $100 to $150. Watch Crappy Tire as they often have this lock on sale and you can price match +10% at HD - we ended up with one of these locks for $92 taxes in from HD after the match + 10%.