Pros/Cons: Using active HPF/LPF vs passive RC filter with buffer stages?

Finally, I have some time to get back into tinkering with circuits again!

I was wondering about some of the benefits and pitfalls of using passive RC filters and buffer stages before and after the filter versus using active filters?
I like the simplicity of using passive RC filters, and in most cases making them adjustable is relatively easy versus using active methods where I may need multi-deck switches to switch several capacitors/resistors at the same time.

I guess my question is essentially, is there anything inherently bad about using passive RC filters and using buffers around them to compensate for loading issues?

Passive RC filters do not allow a large choice of alignments. Only 1st-order is Butterworth (maximally flat). Any higher order is overdamed, giving excellent transient response at the expense of poor roll-off at the corner frequency.
Active RC filters allow almost any type of alignment, including Bessel (best transient response), Butterworth, Chebyshev (higher slopes), whatever... but there are some risks when using high-order configurations (such as 8th-order). In that case, some of the filters have a high Q, and could clip if hit at the max boost frequency.
Making an active Sallen & Key filter up to 4th order is just a matter of finding the right potentiometer; the topology can be adjusted for using pots of same value.
I tend to favour state-variable filters, because I can use Lin pots, which are easier to find in multiple-gang than RevLog.
Now if you want a 2nd-order HP or LP, you can go passive, it won't make much difference in terms of results.

+1 to what Abbey said.. The passive with buffer vs active, for simple one pole filters are 6 of one half dozen the other, since the buffer is generally an active device.

About the only place I can think of where passive filters have an edge over active is for LPF dealing with extremely fast slew rates. I noticed when designing anti-alias/reconstruction filters for BBD analog delay lines back in the '70s that active filter sections often had trouble dealing with the high slew rates from clock noise spikes that would show up in BBD outputs. OTOH, simple passive LP filter poles, would always be rock solid, cleanly rolling off whatever I could throw at them. Since odd-order multipole filters are usually a mix of 2 pole sections and one real pole, I always placed my real pole right at the source of the highest slew rate noise, and after that real pole, all the active sections that followed were well behaved (including the modest speed opamps available back in the early '70s).

While modern opamps are much faster, I have stayed with my old practice of trying to always use a real pole at the very input of my audio paths so all the following active stages will never be over stressed by too fast a rate of change.  Happiness is never slew rate limiting.  8) 

JR

Thanks guys, that helps a lot!