I was totally a blowpipe believer. Then I played bunch of time. Now it's 100% clear (to me) that javelins are the better option.
I'm on the Jav side of the fence, too. However, if you're running lots of units of skinks, I would sprinkle in some blowpipes. Maybe 3 Javs and 1 Pipe.
I've been running only blow pipes since September, not that I think they are better but I just haven't tried javs yet. My main use was as Warmachine hunters and I like the odds 20 poison shots gets me for the 3 poison needed to wipe out a machine
Over the course of a game, I think BS3 Quick to Fire nets you more additional poison shots than BS3 Multiple Shots. That's why I like the mixture. 3 units of Javs to run ahead, redirect, shoot at stuff, and generally be a nuisance. And one unit of blowpipes to sit back and wait for something to get within range so that it can fire off 20 shots and only have one of movement/range penalties.
Well that's the key with my use of skinks. Using the movement penalty to close with the range. I generally go for a surrounding tactic rather than the approach just inside range and fire it harms my flee reactions but I never really anyways lol. It's been working for me but I'm looking to add some more skink units to control movement better
Javs. We have blowpipes on chameleons where they have the +1BS to use the double tap and ability to scout to get in range faster. Of course, cohorts have no choice and the utility of skink cohorts in terms of a chance of taking a charge by something with no ranks and remaining steadfast and being able to stand and shoot at short range or take a Korx for the LD and maybe hitting power when charging a flank or rear means kitting out skinks with javs is worth doing. The quick-to-fire is really key for getting up close and still being able to stand and shoot and force a charge. With flying stuff and high M in the game, it is just too easy for you to have to stay at long range with blowpipes for both bait and flee and for stand and shoot purposes and having to constantly move and shoot at long range completely negates the benefits of blowpipes relative to javs. Long-range + stand and shoot means no double shot. Long-rang + move means no double shot. Additionally, long-range + move with javs hits on 5's whereas blowpipes hit on 6's with no double shot. The only only time blowpipes seem superior on skinks is when skirmishers I can use their free reform and march and shoot ability to reliably get in short range and get on flanks and behind stuff so as to avoid being charged. I am also surprised at how often that extra +1 AS or parry save of the shield in combination with the 6+ scaly skin saves a skink or two in a unit and ends up being the difference between being destroyed or not in combat (forcing the opponent to pursue and not able to reform or risk letting you save some VPs), having the unit destroyed or not iwhen targetted (forcing the opponent to spend more effort for the VPs), or having the unit not being able to rally when fleeing or not having to take a panic test when targetted with magic or shooting. Playing against LM more than with it, I can tell you I have a lot more difficult with skinks with javs than blowpipes, especially with my dark riders in DE armies (M9) and furies and screamers in my daemons army. So many times I have set up and then charged a unit with blowpipes and killed it before it even got a chance to do something effective and the unit could not get off a stand and shoot even due to the movement range of my units. With the lower LD now, when skinks flee those units are more likely to remain out of the battle longer because they have no musician for the +1LD to rally unless they flee back into range of the general or BSB. Fleeing skinks through other skink units outside the range of the general or BSB can similarly lead to a cascade of panic tests with some failing.