1. I purchased a new Dell tower a few years ago. I returned the new monitor due to the horrendous refresh rate that cause my monitor to flicker within 30 days. The replaced it with an awful BUT REFURBISHED monitor. "It was their policy." BUT I BOUGHT IT NEW AND IT WAS DEFECTIVE! I was told, "They all work that way." I escalated it and lost the battle. The monitor went into a closet until my old monitor finally died. Then I had to deal with the flickering for a couple of years.
2. Within a year of buying Dell's tower, it had so many problems and customer support was so script-oriented that I replaced it with a Gateway that I still have and it's great and customer support is knowledgeable. Dell's customer support told me to do things to my computer that I knew would totally mess it up. I also had to escalate each time I called to get someone who I could understand (or hang up and figure it out myself).
I stopped buying Dell. A friend of mine had similar problems with her expensive 8200 series. She was on the phone for hours trying to fruitlessly get problems resolved.
I don't know if they have changed, but problems with a tower and a monitor and horrendous customer support are enough reason for me to never purchase Dell again.