The telephone quality is OK, but sometimes sounds a bit like. "Underwater", but this may be due to simyo (E-Plus) Whether the voice quality with other providers is different, I can not say. In general, it is yes, the network of E-Plus is not the Bestausgebaute, and at first I had the mobile Internet more frequently misfires, but I have to say that this has actually improved in recent weeks - outs I had now for some time not more (valid for the area east of Munich).
The camera of a mobile phone is of course not to compare with a DSLR or a compact clippers, but for occasional Schanppschüsse they certainly have enough of. However, the autofocus responds not always accurate, and plenty of light, they also need to make reasonably acceptable images. However, the barcode scanning or Goggle function properly so - even in low light conditions.
GPS I have not been extensively tested - usually I have it disabled. The location detection via wireless usually works well (assuming, of course, there is a Wi-Fi near).
The battery life is enough for me at about 2 hours daily online experience (web, email) for good, a day - two days I create only on weekends, where I use the less mobile. With JuiceDefender I left after a normal day for about 50-60% battery capacity without JuiceDefender maybe even 30%. Here, Wi-Fi is in standby mode, and JuiceDefender goes every 15 minutes via mobile online in order to let the apps synchronize their data. In normal use, I have the phone once a day charge (I load it up at night).
With regard to the stability, is this well in normal operation, in my experience. The battery to take out because the phone has completely hung up, I had never before. However, it sometimes happens that after the nightly charge after being disconnected from the charger (original), comic responds - everything hooked and then paralyzes, and the home screen crashes. In these cases the examiner has only a reboot. Whether Android 2.3, which has been so announced since the launch of the Black, but not released until today, will resolve these occasional stability problems remains to be seen.
Among the pre-installed apps, I will not say much, because these so easily be replaced by alternatives, if so should not be satisfied. As a browser I use, for example, the "Miren Browser" for emailing "K-9 Mail". With the onscreen keyboard, I am doing something hard (buttons are too small for me) and I have, therefore, the "Big Buttons Keyboard" installed, the me I am much less frequently mistype.
A comparison to other smartphones, I can not draw, because this is my first smartphone. And despite the little quirks I kinda fell in love with it. :)
As an accessory I recommend the "LG Electronics Flip Leather Case CCL-310" and "atFoliX FX-Antireflex screen-protection film" (see my reviews there).