Wow! I am impressed.These strings are awesome. For anyone who likes D'addario Xls,i urge you to try these strings.They are very similar to Xls,but i like the Markleys a little bit more.They don't have that chorusy sound out of the box like the Xls have,and thats a good thing.They feel very much the same,which is smooth and very playable with just the right tension for slapping.I use 40-95 gauge and there is no floppin' going on. All the way around i like the sound of the Markleys' more.And unless they go dead in a couple weeks from now,these are the better strings. In conclusion... I don't understand why Markleys' aren't more popular.These are really great strings. And i imagine there other ones are really good too.What gives?