Hello Lutz (and welcome to the forum, by the way!) - I think you will find that the V60 is actually a Piko model, but the V52 is LGB. Piko locos usually fetch less money than LGB, they are considerably cheaper even when brand-new.
The Piko V60 is, as you know, a model of a standard-gauge loco - I think Piko model them to around 1/26 scale which is not really accurate for either standard OR narrow gauge, but kind of "looks right".
The LGB V52 has been made for many, many years now in several different versions - they are very good and reliable locos, excellent runners and look good hauling either passenger or goods stock. If it is one of the versions with DCC and sound, then it may well fetch a reasonably high price in the end.
Personally, if it came down to a choice between the two then I'd go for the V52 - but the V60 may well sell for a lower price, so if your budget is tight then that would still give you a very nice loco.
Jon.