Nice work!

Regarding sync speed: Bear in mind the python server implementation has a per address throtteling in place to avoid DoS. One of the shortcomings of the current python implementation is that one client with lots of addresses can hog server ressources to a point where all other clients are hanging in "sync" until the large request with lots of addresses is served. To avoid ressource hogging by one client throtteling per address was implemented and works rather well as a workaround.

[Edit: spelling]

They'll probably be treated like no-fee TX by pools who have upgraded to 0.9.0 - at least now they have a chance to propagate where previously they'd only propagate if they matched the strict rules for no-fee tx. It's really experimental at this stage to get them into a block because even bitcoin-qt in core sets the old  0.0001 fee as default to send tx.

I believe it should work - there was a fix applied to servers especially for this. There may be some older v0.9 servers which run an old version of the database (v2) where it doesn't work. Can you test this with electrum.no-ip.org for example? This is an up2date server. If it works, can you please point out the servers which don't yet work?

Thanks for the update. Nice map! Berlin has two servers BTW (eco-electrum.no-ip.org and electrum.no-ip.org). They look like one on the map, maybe you can move them next to each other like the Hetzner-Cluster

I'm running headless bitcoind on the Electrum server foundry ( http://foundry.electrum.org ) without problems. It all works as expected. It's nice to see some proper timestamps in the debug.log now.

One thing I noticed:
2013-12-09 14:22:59 Bitcoin version v0.8.6.0-g03a7d67-beta ()

-beta is probably not intended for a production release?

There were quite a few more improvements to the server code in the past week! OPs are encouraged to git pull.

If you haven't pulled in a while: The server does no longer require bitcoind to be patched. You need run bitcoind with txindex=1 instead and may need to reindex once if you're adding the setting. Please see the HOWTO which is up2date: https://github.com/spesmilo/electrum-server/blob/master/HOWTO.md

This issue should be fixed in 1.9.3 - Win/Mac builds will be available some time this week.

#372 is fixed in 1.9.3

This issue should be fixed in 1.9.3 - Win/Mac builds will be available some time this week.

1.9.3 should be a lot better with less tx rejected errors. 1.9.x notifies you if the coins haven't matured and we were able to fix two bugs which prevented tx to be sent (dust change, signing after a tx was rejected)

This issue should be fixed in 1.9.3 - Win/Mac builds will be available some time this week.

Yes, this is standard behaviour. The password is used to protect your private keys (the seed). It's needed when you want to send a transaction for example. If you want to protect your wallet from prying eyes consider putting it in a true-crypt volume or similar.

There were some issues with dust output and signing after an error sending a transaction occured. 
Those should be fixed in 1.9.3 - Win/Mac builds will be available some time this week.

This issue should be fixed in 1.9.3 - Win/Mac builds will be available some time this week.

The way I understand is as follows:

There is no way to determine (all) other public keys of a deterministic wallet from knowing a number of public keys belonging to it. You need the so called "master public key" (MPK) to do so (also known as wallet without a seed). If this becomes known and the rest of the assumption holds true then only ECDSA needs to be cracked, right.

However if the MPK and just ONE private key is leaked the other private keys can be derived.

So spending in electrum is no risk for the deterministic wallet. Leaking the MPK can become a problem - for your privacy and because only one private key is needed to break the rest.

TL;DR: using electrum to spend is no security risk for the vectors mentioned by the OP

To server ops: You can upgrade to bitcoind 0.8.4 without any problems with the current electrum-server code. Just apply the known patch and compile.

I've updated the howto accordingly: https://github.com/spesmilo/electrum-server/blob/master/HOWTO.md

The error code is issued by bitcoind refusing the rawtransaction from electrum-server. It's usually because the coins are already spent in some transactions already or are unconfirmed inputs.

It may also be because of the size of the transaction if you have lots of inputs and the fee. Try increasing the fee a little to say 0.0005 rather than 0.0001 and see if that makes a difference.

If it persists over restarts - it's rare but possible that the blockchain_headers file got corrupted or it downloaded corrupted chunks. Please close electrum, find the blockchain_headers file, delete it and restart. It'll re-download it which will take a moment (20 MB) and then ideally it should fix your problem.

Did you restart Electrum during these days or did you leave it running and set your PC / laptop to hibernate?

There are instances where a restart of the client ist needed to show transactions as verified...

If this is still an issue try changing the server and if that doesn't work recover from seed...