A $300 camcorder will not provide "good low-light performance". And everyone wants that.
A $300 camcorder will not provide good audio when the audio is really loud or really soft. And everyone wants good audio. If you have friends in a band that uses amplified instruments, this will be too loud and it will sound REALLY muddy. If there is complete silence or very low audio, the auto audio level circuit will "listen" and you will hear a "whooshing" sound when you playback.
A $300 camcorder will not come with a long lasting battery - none of the consumer camcorders come with one - you have to buy an extra optional high capacity battery so you can record more than 20 minutes or so before having to recharge the battery that comes in the box.
The zoom on a $300 camcorder will be only "OK"... and if you want more, you typically cannot attach a tele-lens. And you never ever want to use digital zoom - unless you want to call the resulting video capture "art". I always suggest turning digital zoom off. It is useless.
A $300 camcorder generally does not have manual focus - so you are stuck with the auto-focus mechanism, whether you like it or not.
There's a lot more, but I'll stop here... Honestly, if you are OK with all this (and the other stuff I didn't mention), then any camcorder from Sony, Panasonic or Canon (or even Samsung or Hitachi or JVC or whatever) in your price range will do... really. Just flip a coin.
What I will say is good is the miniDV tape quality of a $300 is WAY better than hard drive based or DVD based camcorders in this price range. If you can find a new Canon Elura 100, get it. There is a reason why it was "Camera of the Year" a couple of years ago. The Canon ZR 850 has slightly better specs than the ZR800, but the ZR800 has a mic-in jack the 850 does not have.