Any comments on my Ayre AX-7e vs Ayre EX-8 vs Simaudio Moon 340i Integrated Amplifiers

I am using my 12-year-old Ayre AX-7e integrated amplifier in my 2-channel home theatre system including the Ayre CODEX DAC and Quad L12 mini speakers. It sounds very good. 

My retailer (same one I purchased the Ayre and Quad speakers from) suggests I consider the new Ayre EX-8 integrated amp-DAC or the Simaudio Moon Neo 340i Integrated amplifier-DAC for improved sound quality.

My concern is my Ayre amplifier is 12+ years old and its circuits are getting old (I do not know).  

The Ayre Acoustics EX-8 Pricing below has several input options:

$5,990.00 (analog-only)
$6,950 + Digital Base (S/PDIF)
$7,450 + Digital Base + USB
$7,650 + Digital Base + Network/Ethernet
$7,850 all of the above

The Simaudio Moon 340i pricing below seems more reasonable (to me):

Base Price: $4,950. Options: MM/MC phono stage, $400; DSD DAC, $900; D3PX edition (all options included), $5,800 minus the MM/MC phono stage, $400, my net price is $5,400.

I am researching an upgrade and am looking at my options.  The Ayre amp is more expensive than the Simaudio that looks very good.  And, yes, I plan on listening to both units shortly.  My current Ayre amplifier and CODEX DAC are located in a cabinet and I need something that is about the same size and does not generate much heat.  Any new DAC requires an optical (ToslLink) input from my LG OLED 4K HDR 55B6P TV.

Does anyone have any comments, or recommendations, on the Ayre EX-8 or the Simaudio Moon Neo 340i DSD DAC or another integrated amplifier-DAC unit?   

As you have a dealer, I would bring in your old amp and see if you can hear any improvement that is worth upgrading to.  I would not worry about the fact that your amp is old.  It's all about how it sounds. 
One could say I downgraded when I went from a Lyngdorf2170 to the ax7e.

However to my ears it was a definitive upgrade.
Never heard any other Ayre products, but currently running the Ayre Ex-8 (fully loaded) in my system to great effect. Unlike either the Simaudio integrated or your current ax-7e and codex setup, this has the not insignificant advantage of building in a superb and comprehensive streaming solution.
From my experience, the EX-8 is remarkably resolved and pacy without calling attention to itself or feeling unnatural the way my Devialet 220 did; the Ayre is no-holds barred superior in terms of overall musicality. While it does not have an in-built killer phono-stage or variable damping like my Gold Note IS-1000, by far the best single unit option for analog-led systems with high-efficiency speakers, but works better with my current speakers which are underdamped, inefficient, and a touch rich (but I love them). What the EX-8 also has is microdynamic excellence, a massive and highly detailed soundstage, natural timing, silky  but not oversweetened highs, and an uncanny absence of grain throughout. It is a remarkably wonderful sounding and very convenient system.
For matching with your LG OLED, the SPDIF on the EX-8 has a useful video mode (which cancels the asynchronous input in order to match your tv's native clock and video framerate).
I cannot recommend the Ayre highly enough for most systems. Would also look at the Gold Note or the new Hegel H590 closely if shopping in this price bracket for a super integrated (the prior for its use of its tube-like low damping setting with high-efficiency speakers, the latter for relentless drive and accuracy with any ridiculous difficult speaker load).