Ask 10 guys and you'll get 10 different answers on this one- the old Ford, Chevy or Dodge debate. The reality is, all the companies you mentioned make solid x-bows, all with their own minor variations on the same theme. I haven't had any experience with Parker, only with Horton, TenPoint and Barnett. I can only tell you what I've had expereince in, so I'll run it down.

In my opinion, here are my overall opinions of these 3 brands:

Horton- Very good all-around bows, good customer service. They're easy to get fixed and find parts for. They're generally very accurate too. Lows- they tend to be noisy (though most x-bows are) and usually not the fastest bows.

TenPoint- Excellent bows- but like you said, tend to be overpriced.

Barnett- Very fast bows with decent accuracy. The noise level of some models is relatively low for crossbows. Lows- not as durable as Horton or Tenpoint- especially the strings. I had a Barnett that would need a string replacement after only 50 -70 shots.

I've heard good things about Parker, but I suspect they are harder to find parts and accessories for, since they're not nearly as popular as some of the other brands.

As far as broadheads, I've used both mechanicals and fixed heads with good success. I like the reliability of fixed heads but have had accuracy problems in the past, especially at long ranges. I'm currently shooting Slick Tricks, which hit exactly where my field tips do and are wonderfully accurate.

Hope this helps!