as a spyder user the best advice i can give you is this
to upgrade your barrel from a stock one to a freak kit will be a massive difference. to upgrade your stock barrel to a excel or a progressive will be a massive difference. to upgrade between a excel / progressive and a freak kit will be a difference but not a massive one
basically any barrel over a stock will be an improvement, but after that, for me anyway, it is more about the cost than the quality
another set to look at is 32 degrees ones....which i think are fairly cheap
personal choice is an excel barrel, but if you can get a progessive from somewhere cheaper then get one of those.....save the money and still get the benefits