To answer a couple of your questions, I just bought a second 201 for my girlfriend's Mother so I think they're a great tablet especially over a TF300.
1) I live in apartment and don't have any reception problem on 2.4GHz, though have an issue with 5GHz. I can see this having WiFi issues, but nothing really major has affected me. In a large house or outside, I could see WiFi being an issue. I can compare it to a Galaxy Note, S3 and S4 and it's unfortunate to say that the phones do have better wifi coverage.
2) I do believe that 4.1.1 is the latest release for this tablet, but to be completely honest I got my first one already rooted (from swappa) and just dropped harry bean on it and haven't looked back. As for the new one I just got, I played around a little with it and it isn't bad at all, but I could see potentials for lag there.
3) the speaker is back facing so it isn't great. If you cover it, it will muffle, but I only watch a TV show or two before bed so I don't use my speaker much.
4) from my understanding, yes the bootloader is locked, there's a process to unlock it and even a process to pull the NVflash from the device to make it unbrickable. But from my readings there's issues with mismatching MAC addresses making it almost impossible to unlock the bootloader on certain primes. I thankfully haven't had to deal with any of that.
My advice, pick one up, preferably pre-unlocked or maybe even pre-rooted, but if not here's some useful links I've found.
Flatline (NVflash pull, do this first from what I understand)
Unlock and install of TWRP on JB
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I337 Stock with crappy ROM