I have tried both building 0.5.3 myself and using the pre-compiled 0.5.1 binaries. The results are the same: the clients are totally unusable.
The CLI client of both versions still has the unbearable typing lag I mentioned last time. Running it with --server and using the web wallet doesn't help. It is very slow. The RPC POST requests have an average latency of around 2 minutes and some of them timeout with an error!
The Qt client isn't better. The 0.5.3 Qt client is very slow and laggy and sometimes won't ever load pages like the market. In fact it completely froze my Ubuntu system (hard reset required) when I tried to load the market in an attempt to cover a short! The performance of the 0.5.1 Qt client was actually pretty decent, but I quickly realized the only reason that was the case was because the blockchain wasn't syncing at all beyond the point left by the CLI client (a problem I mentioned last time with v0.4.27.2), meaning its completely worthless.
So basically there is no properly functioning client for me at the moment. I only have 4 GB of RAM on the laptop so I didn't expect super snappy performance with the full client, but this is just ridiculous. It has to be some bug in the client right? Or is my computer somehow messed up?