Advice on bookshelf speakers (Sierra 2, Buchardt, Monitor Audio, LS50)

Hello all. I'm interested in feedback from anyone who has experience with some of the listed speakers. Here's my long short story... after heavy interest in audio very early in my adult life, I lost track for a number of years (aka we had a kid) and have recently gotten back into stereo enjoyment. I have Monitor Audio Gold GR10 speakers which are from around 2002. Honestly I have no major complaints about the speakers' performance but I'm interested in exploring new things and seeing what might be available now after 15+ years of technological improvement in speaker design (ok, I know some 40 year old ones still sound great but stay with me here). I also have a pair of Monitor Audio Silver S6's (older ones from maybe 2004) which being floorstanders have obvious bass differences from the bookshelf GR10s but otherwise are clearly (to me) not as good.

What I'm Looking for:
Any listening experience you can share regarding these speakers (or similar):
-Ascend Acoustics Sierra 2 (I've read great things about these but have never heard a ribbon tweeter in my life and have seen conflicting info saying they are flat and clear like LS-50s and others saying they are nothing like LS-50s)
-Buchardt S400 (The way I've heard the sound described seems like what I like in a speaker)
-Monitor Audio silver or gold bookshelves (for comparison to speakers I am familiar with)
-KEF LS50 (which I recently bought and do not like - see below)
If you can compare them to each other, that's great. Or if you've heard any of them and can describe the sound the produce or what kind of music you think they're good for, that's great too. Floorstanders are not an option for me due to spousal and child constraints.

What I Listen to:
While I enjoy classical music, I only use it as background music when I want to relax and don't do any critical listening so I'm not worried about classical music performance. Music I really LISTEN to covers a wide gamut from rock (sometimes hard), a lot of electric guitar (I used to play fairly seriously), some jazz (love me some Nat King Cole), "modern" female vocals (Norah Jones, Adele), and a bit of electronic craziness thrown in like Bjork and Jamiroquai. Glancing over a recent session I see Incubus, Stevie Ray Vaughn, Norah Jones, Tony Bennett, The Police/Sting, Sade, U2, and Morcheeba. Yes, all over the place. Maybe not your taste but I think it's important to understand the type of music the speakers will be used for.

What Kind of Sound I Like:
I am sorry to say I am not well versed in using audiophile adjectives to describe speaker performance. In my own words, I would say I like lively or punchy speakers with clear (bright?) highs but not bright to the point of harshness or fatigue. I don't like mid-range to be too pronounced. I remember as a kid playing with old stereos that all had EQs on them, I would set it in a V shape, turning down all the midrange frequencies. I like the sound to draw me in and make me smile and want to dance. My GR10 bookshelves can do this on some music. A bassline kicks in, or the chorus swells, and you feel that dynamic energy in the room. The KEF-LS50 can't do this on anything. And when I say punchy, I don't mean lots of bass. I have subs to fill in the low region. But the LS50s sound very flat to me - I don't mean flat frequency response, I mean they just sound like they perfectly produce a sound but have no emotion behind it. It's perhaps a lack of dynamics. The best analogy I can draw is when you turn on Dolby volume control which eliminates peaks and valleys in volume. The speaker gives me a feeling that everything sounds very clear and vocals are amazing, but it's not very dynamic, almost like no matter what is happening in the music it's all the same volume level.

Where I Listen: 
This is a family room setup in a great-room style room (aka big and open). Most listening is done standing up and moving around the room but when I really want to listen closely I usually stand in the sweet spot right behind the couch. The sweet spot is not noticeably better than other areas around the room, though, which is important to me. I'd prefer good dispersion since it's rare for me or anyone to be in the sweet spot for an extended period. The speakers are 10 feet apart from each other and a minimum of 10 feet and up to 30 feet away from our ears, depending where we are in the room or what we're doing.

Associated Equipment:
I have various gear around the house but amplification will be from Musical Fidelity - either an A5 integrated amp or an A308cr amp (both 250wpc so more than enough for any bookshelf). Source is mostly high-res Tidal streams coming via Roon to a PS Audio DSJr DAC. When not using the integrated amp, my weak link is my preamp. Currently (also due to spousal and size constraints) I am using a Marantz receiver, with the pre-outs run to the MF A308cr. Some of those things may change but suffice it to say power will never be a problem. I also have a 12 inch Sunfire sub currently mated to the GR10s and in another system/room I also have a Rythmik F12se.

Thank you and sorry to anyone that made it through this long winded post. Any feedback at all will be much appreciated. And if anyone has questions for me about any of the equipment I have, I'm happy to share.

Correction, S400, not S300...
Thanks to everyone for replying. I've been furiously reading about all the above mentioned speakers!

@b_limo Yes I thought the same thing about the S400's waveguide tweeter. Everyone seems to indicate that you can move about the room with little to no change in tone from the tweeters. That is very appealing in my situation. And I did see the review from Z Reviews, plus a couple other similarly positive ones from Thomas Stereo and Zero Fidelity. I also contacted Mads Buchardt directly and described my setup. He basically confirmed that the S400 was specifically designed for my type of application (not necessarily the large room but the bookshelf setup with little breathing room). He said in his home he has the S400s so close to the wall that the binding posts actually touch it.
I listen to a lot of the same music as you, and am enjoying my s400’s with all of it.  I have them about a foot from the wall, and sit about ten feet away.  I’ve only partially broken them in and they seem to be getting better every day.  I would describe the sound as very clear, and sweet.  They sound great at low volume, better at higher levels.  If you have any specific questions, I’ll be happy to try and answer them. 
I disagree with the tweeter dispersion comments regarding the Sierra2's. Yes, when speaking about most ribbon tweeters, vertical dispersion is lacking compared to domes. But the RAAL tweeters set themselves apart in this regard. They are truly special ribbon tweeters. I have enjoyed my Sierra's for years.
Measurements from Ascend’s own site  
It’ll still sound good around +/-10° vertically, which is 6ft is about +/-1ft.