The products from Bivolino have been excellent. The cut and the fit is great especially as I am broader and taller than average, off the shelf shirts just don't fit me well. The website can be clunky at times but generally ok once you get used to it.
The products are great and the after sales care has been excellent.
Improvements or suggestions
I find on the website, when designing shirts, it can sometimes get stuck if you select a tab by mistake you can't get back to the one you want and I end up starting the design from scratch. I think the site could be better but it does work well enough once you get used to it.