Help me decide on these 2 laptops?

Here is a link to the PassMark CPU comparisons between the two. The Dell has the Intel i5-6300HQ quad core processor. The Lenovo has the AMD-FX8800P (it's listed on the best buy site if you scroll down). The Intel CPU wins out as expected (you'll need to copy/paste because I think the link doesn't work properly):

=2632&cmp[]=2567]http/www.cpubenchmark.net/compare.php?cmp[]=2632&cmp[]=2567

These are synthetic benchmarks, so take them with a grain of salt. However, Intel has been producing better chips than AMD in general since 2006 and it looks like that hasn't changed significantly.

I couldn't find much info on the R9 380 in terms of benchmarks. I've only seen very little information. The 960m has been used in many laptops and there's plenty of info on it. Notebookcheck classifies the 960m as an upper mid-range graphics card for notebooks. It classifies the R9 380 as an upper mid-range graphics card for notebooks. Again, grain of salt with regards to what that means. I've only been able to guess based on the specs of the card. But maybe the R9 380 is significantly faster... I can't say. But with the 960m, at least you can find out exactly what you're expecting for that card and its performance (see links below).

960m: http/www.notebookcheck.net/NVIDIA-GeForce-GTX-960M.138006.0.html
R9 380: http/www.notebookcheck.net/AMD-Radeon-R9-M380.147253.0.html

I've seen build quality go both ways. Few companies have truly stellar low-cost and mid-range laptops. Usually, you'll see better parts and build quality on more expensive laptops ($1000+). You can probably look at some reviews to see what others have complained about and take that into consideration. I personally have never owned a Dell or Lenovo laptop so I can't comment. I've had friends with good and bad comments for both, so they seem to come out pretty even to me.

Take a look here also: http/www.laptopmag.com/articles/laptop-brand-ratings

It doesn't make your experience with Dell any better, but it's just some more information. This is also from 2014, so, more grains of salt to be taken!

To be honest, the Dell stands out as the better laptop in my opinion, on paper, if all else is equal (build quality, weight, service, battery life, noise, keyboard, trackpad, screen quality, heat, etc). Of course, not all else is equal, so you have to weigh the specs with the differences in those factors and make the best decision for you. The SSD and CPU are the stand out features for me. If you plan on upgrading the HDD in the Lenovo for a SSD, then that won't matter as much, but you'd also need to spend another ~$100 to get the SSD.