At my wits end with xps17 - Dell support is no help

Not sure why I'm even posting as I have 0 hope now of getting anything resolved by dell.  I bought my Dell XPS in Feb of this year and paid $2500 sticker price for the top model.  Since that time, it's been a pretty horrible experience.

When the laptop works and it does, it's a great machine.  So kudos for Dell for designing and arcthitecting it.  The issue is that when it does decide to act up, it's next to immposible to have the situation resloved.  The first time was in March when I was on a business visit in Australia, after few days at client site, the computer refuses to turn on.  After begging and haggling with Dell support to send a tech out (As Australia is not my home country) they finally agreed and fixed the laptop.  The issue was the motherboard and the power button.

Come June, the same issue, at least this time it's in Canada and they once again send out a tech to the house to get it fixed.  Two weeks later the same problem and once again I get on the phone and I ask for a replacement of the laptop as I no longer have any trust in it.  They refuse to ship me a new laptop but inisit that I send my laptop with data to their warehouse for 2 weeks where they can diagnose.  As a private contractor, this is my work.  What the heck am I suppose to do for 2 weeks without my main computer.  So, I just decided that I can't go on without the laptop for 2 weeks and get them to come out agin.  They change the motherboard and the power button and off they go.

Now I'm at a client site not too far from Dell HQ in Texas and once again the laptop is down for the count.  Call them up to see if they can send someone over as I absolutely need a laptop to do the work and nope, since it was after noon the best hope I have is Friday morning or evening to have someone come out and once again change the motherboard and the  power button.  

I ask the guy for customer care after relunantly transfering, the customer care agent comes on and says that their systems are down and for me to kindly call back tomorrow.  

So...What's going on Dell?  Is it really worth your time to send out technicians 4 times than to just own up on some issue and send me a replacement already.  I don't care about the money I'm losing, but I'm losing credibility with my clients when my tools don't hold up.  The amount of time I wasted with you guys is enogh to make me look at Lenovo from now on.