Ive owned a 2 XL but currently own an XL... The 2xls are still quite expensive, but the minimum is 64GB, the XL can be found for fairly cheap now at about £150 - £200 pre-owned, but youll mainly find 32GB kicking around, although Google is still offering unlimited cloud storage for the XL.
HTC also gave the XL stereo speakers, but Google disabled them... however, theres a mod on XDA to re-enable them on the XL, but I believe you need root first..
Depending on where you live some XL owners have complained about overheating issues, dropping / dead phone calls and battery drain.. although they mainly seem to be centred around the verizon CDMA version.. so if you do buy pre-owned see if your store has a return policy (avoid ebay though), In UK we have CeX who have a 48hr try and exchange policy..
Some owners have also complained of "AMOled / Pentile Burn-in" on the screen (yellow-ish patches) .. so check the screen using a white background before buying ..
Good news is though, XL security patches is still supported until Oct 2019, but no Android Q.. so another year yet..Yay

.... Its a great phone.. great speaker, awesome camera...
Well worth the money..