I use these strings as a backup to Argentines. They are good but not as good in my opinion. I use them on my Gitane guitar for Gypsy Jazz and they do the job. Not quite as warm as the above mentioned strings however.
I've used Savarez Argentines, the D'Addario GJ strings and these.
The Pyramid strings sound very good. Not quite as 'throaty' as Argentines, but still fairly good. Much better than D'Addario. Because they are also much cheaper, these are now my go-to GJ strings.
One thing I've noticed is that they tend to wear out much quicker than electric guitar or bass strings. However, this also occurs with other brands of Gypsy Jazz string. Also you can get 3 packs of these for the price of 1 set of Argentines, so it's not an issue.