What are the weak points of Pass amps and pre-amps ?

As a new owner of a pair of 260.8's and still in the 'new car' stage I can appreciate a number of the responces you have gotten. I moved from a ML333 which I liked very much to the Pass. As far as weak points, I have yet to hear anything that I would consider a weak point but again, I have had only one or two days of serious listening thus far. I do like the way vocals seem to be handled as to me, they seem to convey a in the room sound, very realistic .The bottom end is controlled and very responsive without being 'in your face'. 

I have tried several genres and have, as yet, found anything they do wrong. I feel that is a good step up and I find myself enjoying music that I have not listened to for a while because I felt that the recording was not very good but details are far more layered with the Pass.

Yes, they tend to get warm, but as far as I am concerned after 8-10 hours no more than the ML. As there are now two I have noticed a slight increase in the room temperature (it is winter after all) I will have to see how they do this summer, but not terribly concerned, the sound out of them is worth any inconvience there

Hi Steve, where the heck are you where its still winter? 
It is Spring here in Michigan.....although a brisk 24 degrees tonight 
I think I will go turn on my amps!

Thanks for the information about the 260.8s.  Keep the comments coming since those were sort of on my list to be interested in.

I recently bought a Gryphon Antileon Signature to replace my Pass Labs X350.5. I will receive it next week. I have owned many Pass labs power amps and mono amps in 10 years of time.

This doesn't mean I will never buy a Pass again. Maybe I will buy later XS-300's. I loved all the different Pass amps I owned. And they made me really enjoy my music.

But sometimes you want to look a little further......

To OP. I have an xp12 pre feeding my xa30.8 into my tannoys. IMO tannoys and pass labs are a perfect match because Nelson Pass voices his amps using tannoys. This is the one time that I do not want more from my set up. The realism and ease to the music is second to none to my ears. The downsides (if any) are the xa30.8 takes awhile to sound its best. 

We really are splitting hairs here.  Yes there are some other real expensive brands that others might prefer over Pass but to these years Pass has always sounded very musical.   They are made in the  USA and the company support is second to none.   No weaknesses  that I can see or hear from Pass.