Asus is always the first choice in my book. Sure price plays a factor in purchases, but more often than not, I get more for my money through Asus, not to mention every laptop/tablet I've owned of theirs came with a 2yr manufactures warranty and 1yr of accidental damage included as the standard warranty.
I have an utter hate of HP because of their service policies, even for large corporations, they have by far one of THE WORST support centers and processes for resolving part replacements. One of my clients went to HP because Dell didn't renew a specific government contract, and now they are regretting it. Not to mention HP changes subcomponents like normal people change underwear; it happens and you rarely know about it. Specifically wifi cards. For the longest time, they supplied Intel 6300 cards and all of a sudden, with no mention, they went to Broadcom cards in the units we order. We had to purchase and replace every single wifi card in 500 laptops because of it.
I can't speak +/- on Lenovo because no business unit I've ever supported wanted to use them. It was always Dell, HP, or custom builds.