There's a lot of info on soldering stations in the eevblog forum archives.
But in nutshell, a reason for choosing either the Hakko FX888 or the Weller WES51 [ or its equivalent in the EU market] is that they conform to IPC soldering standards, and thus are equipped to provide the best soldering conditions as studied by decades of arguments of what constitutes good soldering temps, technique and construction. The user experience bears this out too. Also, they are probably the cheapest IPC conforming stations from a reputable maker, as well as low cost to maintain in terms of added tips and spare parts.
There are of course many other stations out there, including the mixed result Xytronic [ whose claim to fame is the invention of the analog temperature controlled station in the 1970] but their quality control is mixed, so you don't know what you actually get despite claims to performing to spec.
As Weller manufacturers in Germany [ as well as MX], they do have better tax breaks for the EU community. You'll likely find Weller a better deal than Hakko in the EU [made in Asia, Malaysia, Japan and Singapore at last count.] Xytronic is worth exploring due to its low cost in the EU, but again, I'd only shop it if I can return it after giving it a thorough performance testing and 'take it apart' QC check.
While I have all the same info on eevblog, I think the questions raised put more stuff in a smaller thread on this other forum:
http://www.electro-tech-online.com/general-electronics-chat/119211-choosing-soldering-station.html#post993132