I've used Virwox a lot times because they're safe and convenient.
I'd just like to add, for your 3rd question, as long as you haven't reached your daily limit (it used to be $140 I think), you can deposit more using Paypal.
So if for example you deposited $50, bought some BTC and decided you wanted to buy more, even if your withdrawal is still being processed, you can use Paypal again to deposit more dollars (up to $90). It's not a problem. Just mind your daily limit.
As you use Virwox more and become trusted, your daily limit will increase and I found that the time it takes for the BTC to reach my wallet also got less.
Also the more you use the service, the less fees you'll pay