After one week with 10536 on my 1520 and twice doing a hardreset it is time to summarize: quiet hours and mobile hotspot fixed. What remains from pervious build(s): store is buggy as hell, won't update many apps and cause overheating, showing wrong languages and crashes unexpected. Startscreen still shows "loading..." just as often as before the update. "resuming..." happens more often than in previous build. Edge is laggy, often showing a blank page instead of loading or crashin completely and loosing all open tabs. System is also not as snappy as before; very obvious when you switching between the open apps. That is just the biggest issues, not to mention the smaller annoyances.
To cut it short: one step forward and directly one step back, not closer to RTM. I am aware it is a preview and therefore not using it on my primary phone but it is still disappointing they push out such rubbish.