mine is actually phoenix but it also goes by cosina and it could be vivitar as well( i know it goes by 3 or 4 names, guessing somebody makes it for a bunch of distributors.) i basically am happy with it. i love the sharpness of the lens just as a 100 mm and use it mostly that way, it's 1:2 macro as is then comes with a 1:1 macro filter that is a little bit of of pain just cause you have to put it on and off but since it was $140 rather than $300-400 i can make due( they had some around $100 on ebay but i didn't get one auction, the one i won the guy sent me a nikon mount and didn't have a canon left and like you i wanted it for vacation so i just bought it new..)the only thing that has been a little hard to get used to is that you really need to be about 18" away or it's not in focus...and i have a tendency to get to close and have to back away.i think that is the fixed focal though, some lenses might focus closer but it just has taken getting used to for me. it's much sharper than the zoom macros i have had but not quite as convenient due to the fixed length. i tried macro filters, manual extension tubes( big mistake) and ended up with this since it costs not a whole lot more than the af extension tubes (on ebay.) it does look cheap though( looks comparable to canon 50mmf1.8 )
and i need a tripod (like any macro ) to get really sharp images and mine is a pain( panning head, i think a ball head would be easier to make fine adjustment)
i googled it an got a number of good reviews even though normally i am more of a lens snob

i'm glad i got it. i have had some
bad 3rd party lenses and had sworn off them but it has made me rethink the 3rd party aspect
there is also a canon 60 mm macro that is recommended for 1.6 crop cameras but don't know the price of it.
i just took a few photos with mine today so after i process them i'll post them. ( didn't use the filter though so they are 1:2 macro and just as 100mm, in the black and white thread not to long ago i posted 3 of my granddaughter that are pink and sepia that are with that lens)