I've been using the same Rotring Ticky almost every day since about 1987. It's the white one - all the print has worn off, the clip is loose, the eraser is flat, the button has toothmarks all over it, I've bent and unbent the nib numerous times, and the case has chips out of it. It works perfectly, and has done for 25 years. West German manufacture FTW!
The others I bought recently out of fear that one day my old trusty would give up. I like the 300, not keen on the Tiikky 2, the nu-skool Tikky is OK but the original will forever have a place in my heart. Or pencil case, at least.