I have a bumber case, Apple gave it to me for $0.00!, and I have no problems. What I have noticed is the signal bars fluctuate dramatically but it has no impact on reception or calls.
I got my iPhone on Friday, the day after release, the signal seemed a bit temperamental on the first day, but has been perfect since the carrier settings were updated.
This issue regarding the signal being blocked hasn't effected me. I have held it in the way which is supposed to drop the signal several times and only notice the signal drop once.
This phone is fantastic, everything works perfectly. personally multitasking works for me, I don't use spotify because I have always been able to listen to the music stored on the phone while I do other things such as e-mails or using some apps.
ehmm, here share some of iPhone 4 reasources and tips ran across days before:
iFunia | iPhone Column
such as video conversion guides, as the iPhone 4 high-definition video clips, watch video on IPhone 4 must be cool and amazing, Im ready for enjoying on the go!
I am very pleased, it's expensive but it actually feels worth it. can't recommended it enough. Gorgeous to look at and an absolute pleasure to use.