We solder about 1.4 million joints per day with Alpha WS809. It's very good.
It prints well (assuming you're screening it) and releases well. The flux is quite active, but cleans up easily with a water wash, and the joint quality is outstanding. We use it for everything from 0201 passives through big thermal-pad components.
Oh, and Just for the record - for hobby work, I suspect any solder paste will work just fine as long as it IS NOT Lead-Free. Those two words are what turn it into rubbish - trust me.
Are you looking for solder wire or paste? For wire I would recommend Kester 44. Just stick with a name brand product like Kester or Weller or even a house brand from a local electronic supplier, just buy either a 60/40 or 63/37 mix, small diameter like .031 designed for electronics work. Rosin core no clean.
Don't use lead-free solder, it's a lot harder to work with, needs higher temperatures and generally is a PITA. You could check if your soldering iron is suitable for leadfree, but then again it may still not be your best choice.
I do believe that even in EU lead-solder isn't banned for manual work and repairs, my electronics shop still carries it. It's cheaper and always works (except for repairing leadfree solder joints... the only good reason to buy leadfree solder for home use)
As far as I’ve heard. I’m no authority but it’s what I’ve heard. Companies love it as it allows for “planned obsolescence” of their products and is good for selling more stuff. There’s a lot of truth in the saying “they don’t make 'em like they used to”.
Lead-free needs a lot more heat than the leaded stuff.
In the UK, the consumer dealers (Maplin, I'm spitting at you) don't sell it. The plumbing stuff usually is leaded and get your own (acid-free) flux. Actually better than flux-cored solder anyway.
If you get your iron hot enough, the lead-free stuff works fine. But remember you are heating the work piece, not the solder - the work piece has to be hot enough to melt solder.
Most soldering problems are from not having the bits hot enough.
But remember that LEDs and drivers don't like heat much - get the iron good and hot before trying to use it. Wait 20 minutes after turning it on before trying to use it.
Remember to clean and tin the iron before trying to use it.
And really, really don't mix leaded and unleaded stuff. Everything Chinese has leaded solder in it no matter what lies they tell.
I still have a couple of pounds of leaded (And fluxed) solder I bought in the 80's. Which ought to last me the rest of my life (I'm 51 in 150 minutes)
But also, there are some UK Ebay sellers that sell lead-solder, for instance http://stores.ebay.co.uk/bingles18/_i.html?_nkw=solder&submit=Search&_sid=837459270
not to cheap, but postage to UK included and we all know a 250gr roll can go a long way in solder land...