iPhone 3G also depends on the provider

Just recently I saw more and more reviews of the iPhone 3G, but some seems to puzzle me because I've encountered no such problems with my iPhone 3G under Singtel. These are some of the problems I've seen encountered by some people:

1. No 3G coverage in many areas
   
2. Time to initialise call is slow
3. Mail can't login into the mail server

I've never encountered any of these severe problems in my usage. The firmware v2.1 has also improved some of the features and stability. For the above problems, my findings are as follows:

1. 3G coverage is excellent in most parts of Singapore except when you're underground
2. Time to call people is comparable with other phones
3. No problem with mail because I constantly use it to reply emails (That's my main usage mode for my iPhone).

I think these problems seem to be more provider specific than iPhone specific. Its not really fair to blame the iPhone for these problems.