I did the same thing. Bought a refurbished Thinkpad X250 and installed FreeBSD on it. Now it use it as my main development machine. I haven't look back since.
I rocked a T43 (from 2005) until 2012, then called it quits, and got a x230 which I still use until now. I always thought I was crazy running a 2005 machine until 2012, but the x230 has been up and running for 8 years now.
It's a very good machine, and it fits in my little blue shoulder lunch bag
It's a very good machine, and it fits in my little blue shoulder lunch bag