Here is were I come clean about the Paradigm Signature S4.
** Disclaimer ** Everything from this point on is my opinion and I dont mean to offend anyone...
About two years back I was searching for speakers and I WANTED B&W Nautilus 803 ... never heard them but I wanted them. I have come a long way since then. I hooked up with the local B&W dealer and listened to the 803's and just didnt like em. In fact it was not a pleasant experience at all. At that time I was more of a nubbie than I am now, so I didnt bother to look at what was powering them, the music source, cables or anything else for that matter. I walked out disappointed and headed to the next shop ... listened to the Paradigm Sig S4's ... fell in love and we were married. Again - I didnt look at what was feeding them. It's now been a couple of years since the honeymoon and I think I want a divorce.
Not that they havent been great speakers ... my system went from a home theater to a two channel tubed hi-bread. I went from being totally disappointed in the S4's to mildly to now quite impressed.
I primarily listened to rock when I bought the S4's : Zep, Rush, Dire Straights, Steely Dan, Phish, Yes, and the like. Through careful prodding I have now gone to more Jazz, Blues, Reggae, delicate female vocals and I'm just starting to get into Classical. This has put new demands on the S4's and I think I am ready to go to a bit more substantial speaker. I'm looking at Revel, B&W Nautilus 800's and JM Labs Utopia. I now love the B&W Nautilus 800's (thanks Mitch) I was a victim of not paying attention. It wont happen again. I'm not trying to knock the S4's in any way ... I'm not expecting them to run toe to toe with an $18,000 pair of B&W's. That being said - my demands have changed. I'm still not a fan of the 803's or 805's but thats more ME than them. They are great speakers in there own right - they are just not a good match for my system and musical taste. When I read your post it sounded so much like me - I had to give you my 2 cents.
For rock I think the S4's are great but a little lean in the bass end. It makes sense - they are fairly compact. For their size they never cease to amaze me. At $3000+ I have been a little scared to push them into that REALLY loud, "I had one too many beers" zone. I added a Paradigm Seismic 12 to try to fill in the low end. It's really great for rock - the Seismic can cause heart failure but again it just never sounded right to me. I'm now running them bi-amped with a couple of older Levinson amps. No problem with power what so ever ... my number 27 never breaks a sweat and neither does the 23.5. To be honest the sub is overkill and doesnt match up well at all for any kind of delicate music at least not to my ears. I now almost never have it on. The sub just doesnt work with my 2 channel system. I have tried really low volume, low cut off, and a few other tricks I picked up from the forum ... still it's just not quite what I want.
Back to the S4's
Jazz and female vocals are stunning to me ... keep in mind I dont have the ear that some of you do. High frequency doesnt sound bright at all to me, yet I have seen the S4's bashed for this. The vocal range is where they really shine. Just stunning to me ... Classical seems to push them into overdrive at times. They are just too small to handle extreme dynamic swings. I also have some live rock stuff that seems to stress them as well. I have taken a beating on more than one occasion for loving the S4's but I have had them now for two years ... changed everything around them and watched them transform into a fantastic sounding speaker. If I had an apartment and listened to Jazz, Blues and vocal driven music primarily, I'd put them up against the best.
We seem to listen to very similar music and have similar equipment upgrade experiences. I dont think the S4's are where you want to go. The S4 can give you the intimacy you seek but you have to feed them correctly and in my opinion, they have the same bass/SPL limitations all speakers that size do. My next speaker choice will have at least a 10" bass driver and I can move the sub straight into the HT arena where it really shines.
PS-I guess that makes me an idiot to - but a happy one.