I need to start assembling some quotes for NTP appliances for our Small-Medium Enterprise environment.

I want something that can pull GPS time, and Internet NTP, and maybe FM radio time.

We currently use our core ASR routers and I want to shift that responsibility off the routers (so they can just be standard NTP clients) and onto something with a precision hardware clock.

We are financial services, but have no requirement for PTP, So I just need NTPv4.

I might upgrade from a standard clock to an OCXO style oscillator, but we don't need Rubidium precision.

I'll probably buy four appliances.
One in each data center, one in each major user site.
Our data centers have historically difficult GPS reception, so I don't want to put all four in the 2 data centers.

The Symmetricom / Microsemi / Microchip S600 appliance is one product we'll get quotes on.

The Meinberg LANTime M1000 is another contender.

The Meinberg SyncFire 1200 feels like an updated M1000, so I'll explore that further as well.

What other products in this space should I be looking at?

Microsemi's Domain Time NTP client for Windows (and other OSes).
Is this something worth exploring, or should I just leave Microsoft's w32time alone?
I hate the way the PDC-emulator is the only device that feeds time into the rest of the domain.
It violates the inherent resiliency of the NTP protocol's design.

As always, the wisdom of the great collective is always appreciated.