Seen from Europe (I am based in continental Europe and did not ask people outside of continental Europe), MDC/MDN is again unusable. It's a recurring topic of discussion in irc.mozilla.org#xulfr because it's unreliable. The following is a verbatim of what happened to me just a couple of minutes ago (my internet cx is excellent and most web sites appear almost instantaneously in my browser):

  • 37 seconds to load front page of http://developer.mozilla.org and page is blank...
  • hit the reload button, 25 seconds to finally load the page
  • type something in the search field, hit return
  • 41 seconds to load and the page is blank...
  • hit the Back button
  • resubmit the request
  • 29 seconds to get results, finally...

Total, excluding a few cycles to hit buttons and type a few chars: 2 minutes and 12 seconds... FWIW here's a traceroute. I finally hit ctrl-C because it never ended.

traceroute to devmo.glb.mozilla.net (63.245.209.139), 64 hops max, 52 byte packets
 1  XXXXXXXX.XXXXXXX (10.0.0.1)  7.443 ms  1.289 ms  1.041 ms
 2  192.168.0.250 (192.168.0.250)  50.786 ms  51.901 ms  55.780 ms
 3  zagreb.magic.fr (62.39.164.1)  58.579 ms  56.553 ms  54.965 ms
 4  ankara.magic.fr (62.39.164.14)  66.834 ms  58.168 ms  56.528 ms
 5  ldc-zagreb-100bt.magic.fr (212.94.166.237)  59.227 ms  55.990 ms  46.902 ms
 6  212.94.163.14 (212.94.163.14)  51.820 ms  50.134 ms  54.879 ms
 7  * 149.144.96-84.rev.gaoland.net (84.96.144.149)  54.568 ms  52.042 ms
 8  xe4-6.cr01.lga01.mzima.net (198.32.118.72)  408.958 ms  142.348 ms  149.950 ms
 9  xe0-1.cr02.lga01.us.mzima.net (216.193.255.166)  321.514 ms  133.631 ms  145.242 ms
10  te1-7.cr01.ord01.us.mzima.net (69.174.120.74)  165.169 ms  178.118 ms  152.361 ms
11  te0-0.cr02.sjc02.us.mzima.net (69.174.120.9)  202.134 ms  309.981 ms  205.233 ms
12  ge1-mozilla.cust.sjc02.mzima.net (72.37.156.166)  197.311 ms
    ge0-mozilla.cust.sjc02.mzima.net (72.37.156.162)  196.931 ms  338.460 ms
13  v8.core2.sj.mozilla.com (63.245.208.50)  201.947 ms
    v8.core1.sj.mozilla.com (63.245.208.49)  198.962 ms
    v8.core2.sj.mozilla.com (63.245.208.50)  412.352 ms
14  * * *
15  * * *
16  * * *
17  * * *
18  * * *
19  * * *
20  * * *
21  * * *
22  * * *
23  * * *
24  * * *
25  * * *
26  * * *
27  *^C
Update: just tried to load https://developer.mozilla.org/en/CSS_Reference/Mozilla_Extensions directly from a bookmark; failed three times with a blank result after roughly 25-30 seconds. Fourth attempt did succeed in 27 seconds.