1. Refurbished Lenovo T420. 2nd gen i5, 16 gigs of RAM. Really cheap for 250$. Just concerned since the cpu is old
2. [A cheap 6th gen core i3 laptop](https://www.amazon.in/dp/B074DYBT2K/ref=cm_sw_r_cp_apa_i_W290zbRF005PZ). Brand new. 450$. At least the battery would last a couple of hours and since it's new it might not break down for another 2 years.
3. A MacBook air. 1000USD. Pretty expensive for me. But willing to Shell out the money if it is absolutely worth it. Concerned about learning the weird shortcuts (and force forgetting them when working on my desktop). It's 'nix but it's really not Linux. I've heard that getting some libraries to work on Mac is a pain - if at all possible. Still worth it? Battery life would be liberating but not sure if it is relevant for me
Thanks in advance.
PS: My desktop has an SSD so I am planning to take it out and put it on the laptop I end up buying.