I've been a fan of Thinkpads for many years now. I think Lenovo has done an ok job keeping up IBM standards but definitely no more than that. They managed to cheapen out the Thinkpads a bit. This is especially true with current T-series screens. I have a T420s (latest) and while an excellent machine in many aspects I think the crappy 16x9 screen detracts quite a bit. Considering it was as much as a Macbook Pro I think they could do better.
With that said, Thinkpads are still a mile ahead of pretty much any PC laptop manufacturer. I would purchase either a Thinkpad or Apple. Wouldn't consider anything else. Oh, and stay away from Dell. I love their screens but their laptops are generally quite bad. Ditto for the desktops too.
The switch to 16:10, then 16:9 screens is disappointing, and it's true that Lenovo could have bucked the trend...but it would have come at a high cost, as a lower-volume panel (keeping 4:3, or 16:10) would have a higher component cost, which would have to be passed on to the buyer. Don't get me wrong, I wish they would, but given that most people don't care (at least not enough to pay extra for it), I can understand Lenovo's viewpoint. That said, I despise the 16:9 aspect ratio, and dropped my T520 because a 16:9 15" machine is just too big to carry around.
IBM ThinkPads were exclusively 4:3, and offered either standard-grade TN panels (unimpressive) or high-end IPS (branded as "Flexview") panels on their high-end machines (T-series, R50/51)_. Unfortunately, Lenovo decided to kill this option as soon as they could; the only Lenovo-branded ThinkPad with this option was the T60, which was really an IBM carryover with a new logo. As the last 4:3 IPS ThinkPad, the 15" T60(p) with Flexview (either SXGA+ or UXGA) still carries a loyal following.
I dearly wish that one could still buy a 14" SXGA+ (4:3) machine still; I loved my T60 with that screen, both for size and pixel density. Unfortunately, most manufacturers are putting the cheapest crappy screens they can find in computers, rather than offering a choice for something decent. Apple's the exception to the rule, as they typically use mid-quality TN panels (and at least still offer some 16:10 panels), but they could easily do better, too.