Well, there are obviously no devices which provide the pure android experience except the GPE editions of HTC One etc.
However, if you like to root, then you can basically buy any high end device and flash a custom rom and enjoy the pure aosp experience. But the Nexus 5 is Google's baby and the awesome support you will get here won't be available elsewhere! Nexus 5 is a cut above the rest when it comes to development
I would strongly suggest you to wait for Google's next update
---------- Post added at 06:51 PM ---------- Previous post was at 06:49 PM ----------
Well, I won't say it's crystal clear but there isn't much muffling on my device. Yes, as rootsu explained, it surely does depend upon the environment you're in.