If you google for <gpsdo "allan deviation"> you can find info on some of the usual suspects.
Here's some tests I've run on various units. Normally, Standard Deviation doesn't work well on oscillators, but since these are locked to GPS, I think it's valid.
GPS Devices -- Measure & analyze the period of the 1 PPS Output
Device ............... Std Dev (ns).... Range (max-min)(ns) ... Device ...... Notes
Navsync CW12 ......... 4 - 5 .......... 20 - 25 ............... GPS Rcvr .... 1,7
Motorola UT+ ......... 40 - 55 ........ 95 - 110 .............. GPS Rcvr .... 2,7
Rockwell Jupiter ..... 10 ............ 50 ................... GPS Rcvr .... 3,7
Motorola M12M ........ 10 - 15 ........ 40 - 60 ............... GPS Rcvr .... 7
Trimble Thunderbolt .. 0.4 - 0.5 ...... 2 - 4 ................. GPSDO ....... 6,8
HP Z3801A ............ 0.1 - 0.2 ...... < 1 ................... GPSDO ....... 6
HP Z3817A / CW12 ..... < 0.1 .......... < 1 ................... GPSDO ....... 4,6
Jackson Labs GPSTCXO . 0.3 - 0.4 ...... 2 - 3 ................. GPSDO ....... 6
NEC NWM-034241-201 ... 0.1 - 0.2 ...... < 2 ................... GPSDO ....... 5
Trimble UCCM ......... 0.09 - 0.11 .... < 1 ................... GPSDO ....... 5
Results are based on multiple runs of ~ 1000 measurements each.
Sawtooth correction has not been used for any of the GPS receivers. Where supported, it would reduce the numbers substantially.
All units were connected to the same antenna system.
Notes
1. Sawtooth correction not supported.
2. Most 'range' results were in this group, but there were a few at 20 - 30.
3. Only one test.
4. Requires external 1 PPS input. Equipped with E1938 oscillator.
5. Measurement made with Fluke PM6681.
6. Measurement made with HP 5370B.
7. Measurement made with HP 5372A.
8. Standard parameters.
9. Optimized parameters. (Not yet used in any tests)