Hotend considerations

Hello,
Please advice about E3D hot ends - I've seen 2 versions one short one long.
As I understand the short will give better printed volume, while the longer will have better cooling.
Are there more considerations that I'm missing?
Thanks.

Are you talking about the v5 and v6? If so, the v6 is basically just better. Its fins are thinner, which allows for enough cooling, even though the whole hotend is small enough to work on a delta machine. (This is the main concern about size, at least for some people -- having a lightweight effector is more important than losing a centimeter of height.) It uses a PTFE liner, though only in the cold part, so it can hit the same nozzle temperatures with less plastic-on-metal friction. This means it can reliably print PLA, unlike the v5 which would tend to jam. Both hotends can print ABS, nylon, PC, basically anything, since they can hit 300+ safely, though I suppose the v5 might be able to go marginally hotter. The largest advantage of the v5 over the v6 -- correct me if I'm wrong -- is that it's cheaper.

The v6 is worth the extra just for the better thermistor fastening.

Most likely its talking about the cheap Chinese v5's, they offer 2 types long and short heat-sink body. If you can take my advise, stay away from them, unless you are willing to take the extra time to set them right they will end up been a headache (specially with PLA) . If it is what you can afford, then buy the long body one, add a permanent "on" fan to cool down the aluminum part and look on youtube for videos on how to fix their issues and set them right. It only takes few hours and worth it.

I bought one of them and the aluminum heat sinks wasn't drill all the way, the heat brake bore was too big but not enough to put a liner in it. and it wasn't even polished. I replace the barrel with an original e3d one, finished drilling the aluminum part, polished and re-tap all the threads. it works great now for anything but PLA, since I have few printers I don't care too much about it and use other one for PLA, but if you have one printer only and thinking of printing with PLA I will recomend having an extra barrel with a PTFE liner in it and swap to it when printing in PLA.