Just a follow up - I found the other article I mentioned on bit quality:
"Woodsmith", Vol. 27/No. 160, August/Sept 2005 - "All about Bargain Router Bits"
I think in general you DO get what you pay for - but that's not to say that you can't spend more than you NEED to (such as shopping at Needless Markup ... oops, Neaman Marcus) - I also don't drive a Bentley but still manage to get around just fine- the spread in costs you were finding seemed a little extreme to me for a somewhat common bit, but I've generally found the CMT bits to be good, clean cutting and they generally hold up well in my experience anyway. That said, I don't do this for a living and am not using them hard on a daily basis. In other words, I don't really need high cost industrial grade bits - median contractor grade bits do fine for my frequency of use and abuse - others would be nuts NOT to get industrial top end grades.
As to "all bits cutting the same", I don't believe that's true - one example would be the shear angle of the cutting edge, even on "straight cut" bits - it's cheaper to make a bit with no shear angle, but a slight shear does make for a smoother cut because it's slicing or paring instead of just cutting/chopping. You'd be surprised at the difference that alone can make, and it adds to the cost of the bit. If it's a bit you'll be using alot, take a look at that - it's worth it even if only for the reduced noise and vibration!
Another thought is that bit makers are in some pretty cut-throat competition - just like all other retail manufacturers, but with an added incentive to be competitive -- the brand of bits you own isn't considered by most to be a status symbol!
If their prices are way out of line with their product quality, they most likely won't be around for too long. However, the low cost - even poor quality - bits we'll always have with us for the obvious reasons.
The advice from GoonMan I think is appropriate - get some less expensive sets first - use them - see what you use most - and then upgrade as your use dictates. No big revelation there, but it makes sense and has stood me well.