"I purchased a pair of the Evo 400 Power Amps and the Evo 400 Preamp last week."

You're gonna have a rockin system, assuming their hooked up to some equally competent speakers. 

It's obvious you're/were serious about playing records(Coincident) so, a report once everything is  online will be welcome.
I am very pleased with my PL Dialogue Premium integrated. I feel absolutely no need to go "Evo" I can't tell what the extra $600 brings to the table.
I purchased a pair of the Evo 400 Power Amps and the Evo 400 Preamp last week. They are delivered and sitting downstairs but I have not heard them yet because I'm waiting for other equipment to arrive. The local distributor has the Evo's installed as well, and he told me via phone that there is a strong improvement in sound quality over the Dialogue series. I can't personally confirm this, as I have not heard them, and I never heard the Dialogue series either. But I can confirm that the amps look amazing and the build quality is the best I have ever seen in any amplifier. For me they replace an ARC VT100 original model which died a few weeks ago which I have owned since its release, and an ARC Reference 2 preamp which I still use. I also own Coincident Reference line and phono preamps which I rarely use although they are very good. When my other equipment arrives in about 10 days, I will report on the sound of the Evos if anyone is interested.

Looks like only the separates [not integrated] for the EVO 400 have balanced inputs [which Kevin has poo poo'd in his past PL videos as being irrelevant] and balanced output from the pre-amp to the balance input for the power amp. It looks like the EVO 300 integrated and EVO 200 integrated both come with headphone amps/jacks. That's what one gets over the Dialogue Integrated for $600 and the Prologue Integrated for $500. There's also an optional MM Phonostage for more [something Kevin has always discouraged having with a tube amp (or was it only a DAC with the same?)]. The EVO 300 and 400 Integrated have DuRoch Tinfoil Capacitors instead of SCR Tinfoil Capacitors. That difference isn't indicated on the EVO Power Amps. Du Roch Tinfoil Capacitors are ID'd for the EVO 300 and 400 Pre-Amps where the Dialogue Premium uses Mundorf Capacitors. The Capacitors appear to be the Sonic improvements.

so all the other "nice-ties" like remote control switching between triode and UL and the bad tube indicator were part of past models too?  Obviously those type of things don't effect sound and seem more geared towards making tube gear seem less "scary" to use by a larger target market.  Hopefully the new model includes features that drive sonics as well.
Looks to me like the new Evo has balanced inputs.  Is that the only difference for 600 bucks?
Maybe I missed it but what is new and improved? Been eyeing the Dialogue HP integrated which is now the Evo 400 integrated for quite some time.