I started using desktop-based sniping tools several years ago, in order to place the maximum bid I wanted without having time for afterthoughts and going above self-imposed limits. The issue I encountered is that my machine had to be on, not asleep, and connected to Internet.
The major concern I had with on-line sniping tools is that I would give my eBay password to someone else and I had to blindly trust them and trust that they would be well protected against hacking.
With Gixen I have a threefold piece of mind: 1) it does no longer handle my eBay password, 2) it provides me redundancy in placing my bid, by using also the backup server at a different location (so far, in several years, it hasn't missed any of my bids), and 3) I can set up a snipe from everywhere and I don't need to be sitting at my computer that runs the sniping program.
I never had the need to deal with the customer service, since Gixen has been rather reliable for me. Looking at the bulletin board I see that they are very proactive in dealing with all issues and glitches.
The service, on my opinion, is fairly cheap and well worth.