Oh dear. I had one try with the new version of Slic3r and went straight back to Kiss. Slic3r took 5 minutes to slice a simple wades extruder housing and produced a 28mb file. Kiss did the same thing in about 30 seconds and produced an 8mb file.
My experience with the new Slic3r was completely opposite. Not unhappy previously but same print with new slice looks better. Same again with variable layer height produced smaller file [expected] and will submit photos of the two when complete.
I didn’t try the latest Slic3r yet, but when I did a a thorough comparison 2-3 weeks ago, Cura came out best (by far). It was much faster and cleaner print.
I was using Slic3r from beginning of my 3d printing adventure (9 month).
Then used Cura few times I liked it very much, but I like Slic3r due to speed settings. I use slower on edges but fast on infill.
New Slic3r is faster, I like it. I will use both for some time.
Yesterday evening we try the new slic3r and in particual we need to print a part with a lot of support. Checking the pure gcode generated it seems improved a lot, more cleaner path (opionion based only on a single piece experience), but honestly, also if I appreciate the new 3D preview, I switch back to Kiss… I miss all the possibility to tweak the gcode creation at lower level, 3D preprocessing and the path analyzer… the main problem for me with kiss is the lack of double color (the multi extruder is only for support generation).
I hope the kiss developer will release a version support the 4 extruders… kraken is on the way 
@Stefano_Pavanello I was encouraged by the new extruder settings in slic3r for use with the Kraken. I want perimeter /infill/support nozzles and that’s not an option with Kiss. I was running slic3r in 64 bit mode, I might try x86 to see if it does better, maybe a 64 bit problem.
I agree, we are trying to find the best overall software and sometimes the thing that one missing is in the other… a super partnership to create a CurakisSlic3r is needed :-). I agree for the single extruder settings and Kiss at the moment is not created for that. I read on the Kiss forum that a new version is in project and will support multiextruder and Jonathan asks for beta testers. I hope to give him some feedback about testing with 2 or 4 head. The problem is that seems that Jonathan is quite not present on the forum in these last period probably due to personal problems/busy.
The main problem and in my opionion the only one with multicolor/support is fighting the oozing… I know it starting to become OT, but what do you use to fight oozing? reduce temperature (warm up) or simple play with retraction… as default Kiss wait for warm up above the piece already printed and this is not good, so yesterday we try to tweak the custom gcode to send the head waiting for temperature (M109) inside the prime pillar… what do you think?
@Stefano_Pavanello Sadly I think that Kiss won’t survive in the long run, slic3r and Cura have too large a following and the weird kiss user interface is a barrier for new users.
Wrt multi nozzle ooze prevention, I intend to use a fast and long retract (10mm) with cool down to standby temp once a nozzle is finished to prevent oozing. Then, when the nozzle is going to be used again, use a custom gcode for pre-priming the nozzle in an area to the side of the print bed (while it gets up to temp) and prime pillar just before it starts on the model.
I’ve also been considering having an area on a corner where there is a fixed hopper that the nozzles can hover over while they prime and get up to extrusion temperature. The hoppers edge would be the same height as z=0 so any ooze gets knocked off as the nozzle moves past it. Hope that makes sense.
@Tim_Rastall I hope Jonathan will continue the development or, if it is not possible for him to maintain it, release the code as open source (someone asks this in the kiss forum); yes, the interface is quite hard to understand at first, but then I found everything more clear than the other two, but probably is subjective.
Regarding the oozing prevention it is the same approach that we are thinking about, so I’m very happy to hear similar from you.
You give me a better suggestion running the pillar after the temp-up and before restart the object