build your own. lenovo is back ordered up the @ss if you are doing a custom build. we ordered 6 identical custom builds 3 weeks ago and its still saying it could be up to another 30 days. i could have build all 6 by myself if 3 days with better parts but my work didnt want me to since our client wanted brand name computers.
plus all of them use crappy mobos and power supplies to cut costs on the pre build/build your own stuff
The lenovo wll outperform the asus computer hands down. i7 beats an 8300, and that 300w power supply is pretty weak for a higher end computer so even adding something as power light as a hard drive might start to stress it.
As far as brand quality goes, I would place lenovo slightly ahead, but ASUS is also a good brand. I would not hessitate to buy ASUS (have two of their laptops) but for your speciric examples the lenovo is clearly better.