Ive been riding bicycles for 25 years, and you can have a good time on a mongoose (pacific). They are not intended for extreme use, but if you just ride dirt trails and roads, Ive know them to last for years.

They are heavy, have cheaper made componets, and you have to treat them nicer. The size may not suite your body geometry as close as a "hobby grade" bike.

Let me put it too you this way, YOU get what you pay for! That goes for about anything.

I bought my kids come cheap china made 4 wheelers. They didn't last .....
I bought them cheap R/C cars..........They didn't last like the hobby grade stuff....
Iv'e had to re-buy things over and over by not getting quality the first time.
It goes for everything....
Only quality made products will take the abuse of daily use.

You can spend twice as much buying cheap products . Look online, ebay, and craigslist.