I've strung many a Babolat and Pacific gut in the 61-64 pound range.
Never had even a slight problem. No knots came undone, never broken prematurely on the stringer or in my bags.
Other guts (cheaper ones like Titan, Unifibre, Genesis, etc)... I have had some issues. I suspect Mamba would be similar to these, which is why they have a disclaimer. Babolat's packaging says "up to 66 pounds" on their VS.
"budget guts" (anything that says "below 60 or below 55", etc... or most guts under $30) *typically* do not come with the quality control and reliability you get with the "Premium" brands: Pacific and Babolat being the premiums.
You get what you pay for. Pacific Classic is the best dollar for dollar out there, In My Opinion. The off-brand budget guts can be worth the risk, but definitely have added risk factors you won't typically get with the Premium brands. I like Pacific because they have three different lines to choose from, and have durability and reliability you can count on. Plus, you know their product will be around, as often the off brands go out of stock or even out of production leaving you in the hunt for a 'similar' string. I've been able to count on Pacific Tough Gut year in, year out. It's more durable than any other gut I've tried as well (having tried guts from many of the premium and cheap brands out there).
Head Pro Tour 280/630 MP, 18x20. Tour Bite 1.15/Mosquito Bite 1.16.
Sampras serve, Agassi backhand and Federer forehand. heh heh
Last edited by JT_2eighty; 10-17-2012 at 07:43 AM.