You should at the very least read through the main Antminer U3 thread - plenty of discussion there: https://bitcointalksearch.org/topic/antminer-u3-discussion-and-support-thread-827356
Yeah, I better do that 
. But, do you own any Ant U3? do you know if there is any equivalent SHA256 miner from another company?
'equivalent' depends on what you're equating it to. I'd assume the small size, in which case there's the R-Box (not New R-Box), the GridSeed Orb (also marketed as GridSeed Infinity and GridSeed Mini and once also sold by LightningAsic under their own branding) and a few devices from TB (Dice, HEX16A4, HEX16B, opinions about that company are very polarized, so be sure to search first).
Some of the latter are considered rather outdated - going back any further and there's the original Block Erupter Cube, BFL Jalapeno, HashBuster Micro/Nano. Things also get a bit blurry as to whether or not they're really in the same sort of category.
Going forward, there might be the Avalon Mini, J4bberwock's SF3301 board (based around GridSeed Orb form factor) and possibly something out of GekkoScience.
GekkoScience are currently also (pre)selling a USB StickMiner if you'd be inclined to go further toward the small device end.
i agree with you sir
