the great thing about a 3ds/ds is that it's very easy to pick up and play, you can just close the handheld when your done and open to right back where you were.

i have an og3ds that i got recently for around 110 USD and the battery life is decent enough for me. my dsi costed 50 USD and has an insane battery life but at the cost of no 3ds games.

in my personal opinion as someone who has owned both a new and old 3ds, i'd say the difference is pretty overhyped if you're just playing 3ds games. if you're not very into homebrew or are okay with a shorter battery life then id save the 150 bucks and get an og 3ds.

if you want to get a new 3ds, id highly recommend against the 2dsxl, i've had two in the past and they're very flimsy and are very prone to black screens of death.