well I'm one of the opinions that mutt is talking about so I'll humor him...lol...
I'm totally against the cheap nickel plated copper metal ones....just something about using a metal tip that is comprised of the same quality of metal that you get from cheap jewelry or gumball machine quality rings that turn your finger green...or that the nickel plating tarnishes quickly and starts to flake off....and exposes copper that when exposed to oxygen will turn green itself...
That being said I won't extol one vendor over another...just saying that that is my main concern over quality..other than that you've got drip tips that come in plastic, delrin, aluminum, and stainless.....and then ther's that nickel plated copper...and those are the only ones I'm concerned with as far as inferior build quality...
any of the other 4 materials I'm cool with...and each has it pro's and cons... the plastics and delrin ones are better if you're using them with cartos because of conductivity issues (there is a chance of contacting the wire in the carto and the tip (if metal) shorting the carto out)... the delrin is a harder plastic and less porous so easier to clean and a bit more microbe inhibiting ..but only comes in black (or white but I don't know anyone carrying white ones)... the plastic ones are available ina 306 atty style as well and their semi transperency is cool...
the aluminum ones come in several colors but the anodization can scratch..but seems smoother (so the
juice clings to it less) and the anodization helps seal it...
the stainless...well it's stainless...it's heavier which can feel off balance on some PVs..but very sturdy, very smooth, easy to clean, very little maintenance...
as for home made ones...I've been playing around a bit with making a mold of a few of the ones I have and casting a few out of a harder food grade silicone...but I havent been really 100% happy with the first couple and it's not a real super pressing project for me....