Juan carlos. just my experience and limited to my EBS cabs....
I have a neo 410 that needed 2 new drivers last year - they had both started to sound a bit 'saggy' then developed a buzz that could be felt as 'scratching' when pushing the cones in and out. I replaced one with a genuine EBS driver that cost a small fortune and the other with a Faital. However, I found the 410 was sounding too harsh for my needs so I've been using a pair of 212s since. Just lately, they sound like the speakers have deteriorated somehow. The upper end still has a nice round punch but the bottom end just sounds overblown - almost 'farty' but not quite how a blown driver would sound. I've tried adding some compression but it doesn't seem to take away the perceived 'looseness'. As i said, this is purely my own experience. I've had these cabs since 2005 so it may just be an age thing but a friends slightly older XSTs sound as tight now as they did back then. There was some discussion on the eden forum around 2003 /4 when eden were planning to bring out neo cabs. They delayed the release because they weren't happy with the longevity of Neodymium magnets at that time. However, they since brought out a range of neo's so presumably they sorted their issues. If you look through the talkbass forum, there is some discussion about NEO vs Ferrite. Like I say, it may just be that my cabs are at least 8 years old and would quite likely have been some of the earliest neo drivers available to the public.. The other thing is, The EBS cabs are carpet covered - an ideal scratching material for my small herd of cats :-(
Hi Jan-Olof. Great to have your input. I'm trying not to go for a huge stack - remember I'm playing pubs and weddings nowadays and size is important at most of our venues so I'm currently thinking about a 2x12 and a 2x10. The Mesa 212 has wheels which makes it even more desirable given it's twice as heavy as the equivalent EBS neo :-)
Also, having re-read what I opened the thread with, I think I may hang on to my amp / preamp for now and change out the speakers sooner rather than later. Time will tell.
Graeme