Are the performance of separates worth the price?

As the previous posters have noted, it is hard to make a blanket statement.
I would ask:
Are you planning to 'upgrade' a lot? then separates are generally better.
Do you plan to keep this for a long time: go integrated.
Do you like to fiddle around with you equipment: get separates.
Do you dislike fiddling around: get the integrated.
Do you have plenty of room? get the separates.
Short on space: the integrated is better.
Bothered by interconnect problems(which to get?) go intergrated.
Like fooling around with different interconnects? go separates.
Hope this helps.
As to quality? for the exact same price, the integrated might theoretically better as single PS and chassis cost.
Also resale? depends, but in the high end, separates are WAY more in demand, and easier to resell...
But then brand recognition and word of mouth on great items makes THOSE items WAYYYY easier to sell than the unknown or bad rep items.

Additional info:

I am considering the soon to be released Jeff Rowland Concerto Integrated vs. Concerto Pre-Amp and Model 201 Monoblocks (or) the BAT VK-300x Integrated vs. BAT VK-31se and the BAT VK-250.

More additional information:

My speakers are Vienna Acoustics - Beethovens
Space is not an issue, expect to keep for a few years, willing to pay the additional price for separates if it is worth it.

Thanks

If you have the cash, go for the separate components. I don't know which would be better for you speakers and I've not heard either brand of electronics, but if it is ultiamte performance and flexiblility you want, than separates are the way to go.
Good listening,
Sgr

If you are going to only have one source, (CD) then I would skip the preamp, get the best amp you can afford and go for a CD player that offers volume control such as the Audio Aero Capitole Mk 2, Wadia, Levinson or Accuphase. You will get a top notch source and a preamp in one package. Some of these units offer digital inputs, so you could run a DVD player into them for HT. You save a set of interconnect, power cord, isolation and shelf space. I love a great preamp, and consider it to be one of the most important links, but if you have a budget and don't need a lot of switching ability it's tough to beat the CD player direct for bang for the buck.