Best all around extruder for school printer

Im working on a new bigger printer with 40x40x40cm buildvolume. Printer will run of 24V and use smoothieware. Im looking primary at direct drive.

So far I have considered:
Bulldog XL with Hexagon hotend.
bq HeatCore Unibody
Itty Bitty Belted Extruder

Bulldog XL is it a bit expensive. How is it compared to RobotDigg version?

bq HeatCore is well priced, but there is some mixed reviews of it. How is it?

Itty Bitty Belted Extruder like all printed extruders takes some time to print and assemble - so it has to be considerably better then off-the-shelf versions.

I feel a bit lost and would really like a few good recommendation.

Edited 1 time(s). Last edit at 07/16/2015 10:37AM by gcardinal.

For such a big print volume the E3D volcano would fit. It comes with nozzles upto 1.2mm.
-Olaf

Quote
o_lampe
For such a big print volume the E3D volcano would fit. It comes with nozzles upto 1.2mm.
-Olaf

Yes, thank you for the tip. But Im primary need advice on extruder - not hotend.

If you are using 1.75mm filament the Bulldog Lite should be sufficient.

I've been using a BullDog XL with E3D v6 hot end daily for 7 months to print 1.75mm ABS and have not had a single failure due to an extruder/hot-end problem.