I ordered one last night, should be here next week.
I am myself a big Gardiners fan, but I have 8 Gardiner brushes and want to try something different. I also have a tucker dual trim but that's about 280 grams and is too heavy for me. This X-line brush seems like a lighter version of the tucker brush, all Dupont bristles and the inner bristles are thicker at 3mm so should give a good scrub.
The last X-line brush I bought I never used, didn't like it. This one looks much better.
Chris-are you using the Dupont one in the link?