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I have had my Rostock working for a few days now and have been using Cura recently since I have heard good things and it appeared to be much faster for certain prints I wanted to do. However I have had trouble with strange bumps on curved surfaces, and some flat surfaces as well. I am thinking it is related to how Cura handles the infil and inner lines, since it seems to be printing them much too fast in the thinner areas, causing serious harmonic oscillations on the printer. I noticed this first on the GyroCube which came out looking terrible and failed halfway (the hot end nicked the print and snapped it off over a few cycles) the fact that the Gyro was the worst looking one hits towards it being harmonic, since it got worse the taller it got, where the part could move more. I am not sure if anyone has had these issues with Cura, or knows how to make it print those areas slower or something (it just goes crazy in there).

Look like over extrusion and possibly an overheating rambo board. I had bumpies (?) like this and the cooling fan for the rambo had failed. Try getting some more air in there.

I stuck my hand in there during some printing today and the Rambo fan was working and it was quite cool in there. The Gyro ball print was at night so it was cool then as well. From what I was reading today the over extrusion thing seems like a Cura issue at times. It could be overextruding if Cura is trying to print to something my wall thickness didn't allow, I had my shell thickness set to 1.5mm and it is possible that the object wasn't thick enough to account for the two sides of the shell. I printed out a small thin walled straight slot shaped object and when printed with Cura the surfaces were extremely rough, and with Slic3r they were clean and smooth. Left: Slic3r
Right: Cura

Other than being different slicers both were the same settings (as far as I was aware) except for the shell thickness which is handled differently using Cura compared to slic3r.

Tomorrow I am going to try and adjust settings so Cura can handle that print without blobs.

You've made sure to change your E-Steps and things like that in the Machine settings in Cura?

If you're using the stock hot end, I've found that having a shell thickness of .9 works quite well for most prints. If you want, I could put up most of my Cura settings for you to try or compare with.

Also, it looks like it's printing too hot.

I should have clarified about my printing process. I was printing Gcode from Cura, through Repetier Host, so the Esteps thing was set to 0 on Cura, which uses the stock one for the firmware.

I am printing with ABS at 210 Degrees (My spool reccomends 215-245) so I dont think it is overheating.

I adjusted the Cura settings to have the Wall thickness of 0.9mm and that mostly fixed the thick wavy walls, however there are still some small dots on it.

I also tried Kisslicer and it appears to work the best out of the three for me, so I am going to try and reprint some of those using Kiss.

That's good you found a solution. Personally I couldn't get my prints looking great with kiss, but I'm glad you did. Many users swear by it.

As for the temp, I was thinking PLA. Sorry about that.

Edit: COULDN'T get my prints looking great with KISS.