which is better : XP COLLIDER or bonus % items

@wadebear well first thank you for the fast and elaborate response

i did built many houses , i regret having so many BROWN though now that i think about it , many kwik-E-marts too , a bit earlier appearently

In mr Burns box I found lemon tree (200 $ n 20 XP) also 30 donuts once- already spent- , but usally it is not worth it, not at this level at least

many thanks , i will follow your suggestions , from now not gonna use donuts. ;) til level 60