Which is better to own a regular kayak or one that you sit on top of that doesn't have sides?

Question

Which is better to own a regular kayak or one that you sit on top of that doesn't have sides?

Answer 1

Depends entirely on what you'll be using it for.  There are some very good sit-on-tops out there good for everything from just doing a little recreational paddling to fishing and even scuba diving.  

But if you plan on learning to do white-water river kayaking, you'll want a kayak that you can fit a spray skirt over the cockpit and eskimo-roll.  Same with surf kayaking (though there are some sit-on-tops that you can do that with).  

For long distance ocean kayaking, a sit on top might not be your best choice either.   Being inside the boat protects you to some degree from weather and cold-water, and for some people it is more comfortable especially for longer duration use.

There are many types and styles of kayaks.  It would be easier to answer you if you said what activity you will be engaging in.  If you're fooling around for an hour at a time on a flat lake is a lot different from sea-kayaking with the Orcas in Puget Sound or running class IV whitewater.