Firstly lets get on thing straight,,,,.....Selvedge Denim is often confused with Raw Denim.., It is NOT. Raw denim is denim that has not been through a washing process or treatment after making the garment. You will usually find this on most well know high street brands where the fabric has been woven on projectile looms, usally 60" wide & produced on a massive scale  
SELVEDGE DENIM is woven on old 28" / 30" shuttle looms ( twice as narrow as the standard projectile loom and takes much longer to weave ) where the edge of the fabric is closed and prevents it from fraying or unraveling and has many different coloured lines that is run along the out side of the seam,where at times you can identify the brand by the colours of the selvedge 
Japanese selvedge denim is renowned for its high premium quality and heavier weight fabric, upto 28oz per square yard and is recognized as the best premium denim fabric on the planet,although this may be true, there are many other Mills out there producing some real high end quality selvedge fabric of which i will come to them shortly  
Just because it says Japanese Selvedge Denim, does not necessary mean that it is any good or any higher quality than the other. This is where the years of experience & knowledge of the designer kicks in. For me, having worked in the field since the mid 80s where there was no computers or internet for research. Making few mistakes by trial and error, I have found that the mills I now work with and have done for some time, have some pretty awesome denim collections that produce the most exciting and innovative fabrics on the planet
The Italian mills, such as CANDIANI & BLUE SELVEDGE( BERTO GROUP) make some really awesome selvedge denim in various weights
Here we have an 11.5 oz Raw Selvedge Denim that was specifically produced for us, by our good friends at BLUE SELVEDGE ( BERTO GROUP) with our own selvedge colours in RED & GOLD. This is what we consider to be our entry level denim where our 13.5oz Zimbabwe Cotton from the Nihon Menpu Mill in Japan is our most prestigious fabric to date. Not that the fact it is from Japan, its the fact that it is the rarest cotton available and renound for its long staple and fades
This is our 13.5oz Japanese Selvedge Denim from the Nihon Menpu Mill
US Denim was at the forefront of the Selvedge Denim Market for many many years with the CONE DENIM MILL from Greensboro, North Carolina since 1891 especially the WHITE OAK Division servicing LEVIS with a good chunk of their fabric until its demise in early 2018
In our opinion Premium Raw Selvedge Denim, although more expensive than your average high street selvedge denim is the best money can buy, it lasts longer and you get better fades, therefore in the long run becomes cheaper  
Our Mills 
Nihon Menpu
Berto (Blue Selvedge)
Hewitt Fabrics
Woven in Lancashire, this is the only Selvedge Denim producer in the UK
At the end of the day its all down to the individuals preference