I did 20 months or so at DHL in the relatively early days. 2002-2004. I was an FO. Came with a rating and left with a rating.
I was lucky. I hardly ever worked weekends. The work was tiring, however my roster was stable(ish)...that said a lot of guys got messed about.
Money OK, but never gonna be any better really.
Pension not good.
Hotels were on the whole OK, some were particularly nice (Villa Grazioli, Rome) some not so nice (Great Southern, Shannon Airport). It all depended on how much sleep you can get as to how much sightseeing you could do.
Time to command was short if you had hours (I didn't and I got offered a modern type and final salary pension, so I left...reluctantly). I believe now the command time is a lot higher.
The guys on the line, most managers and all trainers were good and fair. In fact the management is now IMHO a lot better.
I lived in Cambridge and commuted. Never got called out off standby once and had no problems with distance.
Most guys enjoy it, but it is a different life and there is NO glamour...believe me!
At the end of the day (no pun intended), permanent nights will age you badly. Do your research and see if you fancy it.
A 3 year bond and big debt is not good if you decide you hate it after 6 months. And a lot of people did just that.