This is Garrett Murray's Maniacal Rage

Issues I’m currently experiencing with my new iPhone 4:

• Proximity sensor failure: The screen turns on and off during calls, which allows my cheek to touch buttons on the screen causing inadvertent muting, hangups, tones, and even accidentally adding a new call and merging them (that was fun). Basically, I cannot make calls without using speaker, otherwise they’re a mess. This issue is widespread (see Apple Support discussion thread, Engadget).
• Signal decrease from metal band: By holding the phone a few different ways, I can drop my signal to No Service. While this doesn’t seem to affect calls in casual use, I can force it to drop a call by purposely holding the phone in a certain way and waiting 20-30 seconds. This issue is widespread (see Engadget).
• Added June 30: Calls Dropping via Pocket: If I start a phone call with a headphone headset on, lock the screen, then place the phone in my back pocket (as I have done for years with iPhones), the call drops within 30 seconds half of the time. It almost seems as though there’s a special button in the back of my jeans which causes the iPhone to shut off the antenna. Oddly, signal strength shows 5 bars. But the call fails. Much like the metal band signal decrease, this is much more of a problem if I have fewer bars to begin with. I’m wondering if my headphones, which have a metal base to the headset jack, are causing interference? This isn’t widely reported.

Additional issue my sister is experiencing with her new iPhone 4:

• Bluetooth headset voice quality: This is a weird one. On all incoming calls, using a BT headset causes her to sound like she’s talking through a pillow. It doesn’t matter how the call is initially answered (speakerphone, handset, or BT headset), the moment she switches to the BT headset the sound quality is terrible. However, all outgoing calls work just fine. This issue isn’t as widespread, but there are users reporting the same symptoms (see Apple Support discussion thread).

I have tried a restore on my phone (both clean and from backup) as well as resetting all settings twice, without success. In all cases, user reports indicate that having the phone replaced does not solve the problem (although, in rare cases, it has). I’m hoping against hope that Apple is preparing a software update that will solve at least some of these problems. I will update this post with further information as things change.

Update, June 30: Walked into an Apple Store today and told them about my issues. They said they would replace the phone. Unfortunately, the wait was over 2 hours. I scheduled a replacement for Friday morning, so I will report back after that happens to see if these issues are resolved.

Update, July 2: Part I of what I learned when getting my iPhone 4 replaced.