There is nothing like it to compare! I have used many great barrels (dye, AA).
Tippmann A-5, Flatline, Palmers Stabilizer.
I have never broken a single ball in over 10 cases. Better paint does get better accuracy, but even egg balls will not break. I like Draxxus for dead straight shots, but mostly I use Zap Rec Series.
You become enemy's #1 objective.
Can be tricky to adjust. (co2, velocity)
I was very worried about my flatline purchase at first, and tried to change it at the last second to a Dye Ulralite. Fortunatly for me I was too late, it had shipped earlier in the day. This is the biggest break through in barrel technology since the barrel itself. I have waited a good while to post my review since it takes some time to get an accurate "feel". After being used to a standard barrel's arc the Flatline is quite amazing. Just when the ball is supposed to drop it seems to float on, this gives an illusion that the ball is slower than normal. I am the only one around my area to own an A-5 or a Flatline, and it is very funny to see their reactions upon firing it for the first time. "Holy crap! Look at that ball fly! It just Floats! Can I try again!?" The accuracy of the Flatline depends on the paint you are willing to buy for it, and also the consistency of your shot to shot velocity. Even with Zap rec series paint my accuracy is very good, as long as my pressure is right. It is perfect at 270 fps, under 260 is not enough and over 280 is too high. This is a pain with co2 being unreliable, so I have bought a Palmers Stabalizer.
I find that you can't get it to curve very much around corners or trees, but you can put it on upside down! Talk about dropping balls, they zoom straight down after 60-70 feet...very useful. Some say they have difficuties removing this barrel. It seems that anyone that says it take 3 bolts does not have this barrel. It only takes 2, and if you want to leave 1 semi-loose, only 1. If you want to be able to switch to upside down mode quickly just leave them semi tight. Or have an allen key and some cover fire (15 secs)
After owning the Flatline a while you get used to the new arc or lack of it, and the novelty seems to wear off. All I have to do though is just switch barrels and see the difference. After alot of cases the Flatline loses its sand blasted surface and must be re done, that is a pain but at least Tippmann does it for free. All you have to pay is shipping The best part is watching unsuspecting people stealth up to you, because they are out of range, then shooting them in the back as they run! This is not a camper's gun however, it gives you the confidence to stand right up and watch everyone.
This barrel owns anything out there! It will kill any other gun in the bush. It is revolutionary, and amazing. Do not let any one talk you out of it, it is the best bush-ball upgrade, and is great in scenarios (building window to other building window etc.) If you want a speed-ball barrel get a Lapco 8' or 12' Bigshot.