I've tried them all. Generally I just have hollow core pencil lead pre-cut and I keep them in an old prescription bottle. I generally fish 2.5 inch chunks but keep some 3inch chunks and some 2 inchers. I put a buzz-bomb bumper between the lead and my knot. I like them better than a bead as occasionally the bead cracks and falls off.
I keep a few L, M and S split shot on me too just in case I feed the need to break them out but I haven't in a couple years. IMO with split shot there is too much time spend pinching them on just right, and sometimes they start to ride up/down. However I do like the look of them better on my line, I just can't be bothered and have not noticed I catch any more fish.
I experimented with that fatter pencil lead and used shorter chunks. I just didn't like the look of it and it seemed like it got snagged up more when I was trying to dial in my float depth. Went back to the regular 1/4 inch or whatever it is.
By far the best river fisherman I know, almost never out fish the guy although it happens on occasion and it drives him nuts, uses this god awful 3-way swivel set up where his lead is crimped to a piece of mono coming off the 90 degree part of the 3-way, has never fished flouro leaders, and only uses the cheapest dink floats. I use more expensive floats etc because I like them and they give me confidence but in the end it really comes down to proper offering (size, color, etc), depth and presentation.