I'm a repeat customer of Dell India for a simple reason; I always get a higher configuration at a lower price than any other notebook or desktop manufacturer can offer. And I can customise the configuration to suit my need.
I have always advised my friends to visit a Dell reseller to gauge their comfort with the notebook (ergonomics, key and touchpad size, ease of typing) but to buy online to negotiate a better deal.
It pays to bargain hard for a good offer. I have gotten the octroi waived off twice (that's a big deal if you live in Mumbai, paying the highest octroi in the country; it translates to a discount of Rs. 4000-5000).
And you can put that money you've earned to a better use. A techie friend advised me to always ask for the extended warranty (they cap it at 3 years, but if you can get a longer one, go for it). It's frighteningly expensive at the rates listed on the website but the good news is that you can negotiate it down too. My friend got a 3 year comprehensive cover at roughly the same price as the limited hardware warranty, which was about Rs. 6000. This may bite a bit for people buying machines for personal use. But it makes great sense for small business/ SOHO users, as anyway, it's a tax deductible expense. And after that, no worries about service. If you're buying a high end machine, or one with a graphics card, take the extended warranty anyway. Dell has had some issues with GPUs in the past and you really don't need to take chances.
The only really weird thing about buying online from Dell India is that you have to read out your credit card number online and punch in the CCV while the sales rep is on the line. Surprising that they do not have an online payment option!
Oh and once the order is confirmed, the sales rep will vanish from your life forever, so be sure to take all relevant mail/phone contacts from him in case there are any glitches with your order. To be fair to Dell, it's been smooth for me 75% of the time, only once my order really got delayed and no one was answerable.
XPS buyers should totally demand the dedicated XPS number, which is the best kept secret on the website. The XPS lines are answered far more promptly than the aam janta ones. Classist, but XPS is..well, XPS.