SN100C vs. K100LD solder?

[stuartk]

I'm tired of the dull looking joints I get when I solder with SAC 305. I've heard that both Kester K100LD and the Nichon Superior/Aim Solder/Stannol SN100C, are both cheaper and better, both in terms of cosmetic performance and improved wetting.

Apparently both of these alloys reduce tin whiskers, corrosion and thermal cracking.

Has anyone use both of these solders and come to a comparison as to which one to buy?

A couple of local shops have some offerings:

$41 canuck bucks for a full pound of the K100LD stuff
https://www.accessotronik.com/product_p/24-9574-1402_k120.htm

$32 for a 1/2 pound of SN100C
https://www.diverseelectronics.com/products/Solder-Wire-0-8mm-032-SN100C-LF-No-Clean-p8066/

I'm trying to find a source for a 10g syringe of paste, not an expensive tub of the stuff. So far no luck.

Any suggestion as to which one to use or where to get a person sized supply of paste? Thanks,

Stuart