As per @la bams post, the ABM600 is def the best amp I’ve ever had, incredibly flexible and powerful, and at 13kg still easy enough to cart about.
I can get the same sound that I want from my RM500, and in rehearsals or small venues there’s not that much difference between them, however get on a very big stage and the ABM has a greater weight & presence to the sound.
I’ll never tire of recommending Ashdown gear, especially the ABM600, unless looking for modern crystal clear highs it’s capable of virtually anything a bassist would want and also capable of a commanding presence on those big stages.