I have been a Dell customer since the 90s, but went rogue and bought a Lenovo for DH for his birthday last June.
BIG MISTAKE! It's noisy, and while it has an i5 processor and the same RAM as my Dell, it's slow. Lenovo refuses to acknowledge that the fan and/or HDD (it's nos a SSD) is overly noisy. It's under a 2-year warranty...BUT...BIG BUT.....there are NO repair centers in the UK. You need to send the machine to Germany for evaluation, and if they say there's nothing wrong, YOU have to pay to get it back.
So, if you are thinking about a purchase, do NOT go for a Lenovo.