I'd suggest that you find the cheapest one that you can, say one from Walmart or Target.
Why ? Because chances are that you will use it once or twice and then it will sit quietly on the patio for the rest of its life until you turn it into a planter.

Unless you like your hair and clothes smelling like a smoky campfire you'll not find the thing too alluring.
You'll have to have your kids take a bath or shower after sitting around the campfire or their bedsheets and pillow will stink of smoke until you wash them.

The firepits that seem to get the most continual use are those that are run by clean burning gas.
You can find these at the large department stores. You simply replace the propane cannister just like a propane bbq.

If you do choose a wood fired pit, check your local code compliances. In many locations ( especially california and other progressive anti- pollution states) you are restricted in using wood burning appliances/ pits.

Thank you. Propane was suggested by others with experience, those who use them a lot.

We're happy with ours, and we use it quite a bit. We purchased it from a high-end store that specializes in outdoor furnishings. The feature I recommend most is what ensures that ours gets a lot of use. It's the height of a coffee table, with the table top made of polished stone. There's a circular removable section at the center, so you can remove that piece to use the fire pit, but it's always usable as a coffee table. It's held up well (outside year-round) for about 6 years so far.

Wow, that Lava thing is $1400!

I second Still_Lynnski's advice, get one that can double as a table & has a cover. Wet ashes are never any fun. The propane ones are very nice as well, I just happen to like the way wood smoke drives mosquitoes away. My choices are usually to smell like a campfire or smell like bug spray. I haven't tried to OFF! clip ons at night to see if they are powerful enough for that job (they work well during the day).

Good luck no matter what you choose, even if its the $1400 behemoth :)