The defensive comments from the Firefox team are missing the point of my OP. Here are the highlights

Complete lack of respect for your users.

Rolling out a new version but calling it a security update, these are two separate things.

It did NOT NOT NOT warn me that it intended to install a completely redesigned application.

Have you guys heard of change control management?

Change control does not mean you test it on a bunch of FF sycophants, it means that you give end users the option to switch on the changes and to roll back.

I have been involved in huge rollouts of MS Office (100k+ users) when the ribbon came, it was so radically different that we had to implement a training program, this is the same.

You have to realize and accept what makes Firefox is the personalization, so DON'T MESS WITH IT. If you can't figure a way to implement it without screwing up people's customization, then scrap your changes. You really ought to be able to offer users a chance to try small changes and roll back if they do not like it. It should be a requirement of all UI changes. Oh and I mean SIMPLE "try and no thanks" roll backs, not some hidden code buried on an about page or hidden on the web.

I still think the important issue you should be focusing on is performance and the ability to see which tab is using resources or leaking memory, I would like to see an option to display the memory/cpu in the tab instead of the title, you could even have the tab go red.

You need to be able to isolate and shut down these tabs, I do NOT think you should have the multiple instances that Google Chrome has because they do not relate to tabs or help in any way to stop a badly performing page.

I think that every time you get an inclination to copy Google Chrome you should slap yourself around the face and if that does not help you should have your team queue up (think airplane movie) to slap you. In fact I think that Mozilla developers should have slaps for stupid or badly implemented ideas.

I hope that you can learn that bulldozing over your userbase is unacceptable.

Now it would be churlish not to mention the best way to copy with this screw up, first I had to install colored tabs, this gave me back square tabs and stopped the awful waste of screen estate.

I then used the (drastically bastardized) customise option to move icons to the top bar next to the menu, they are very small and it would be good to have some option to increase the size.

I have the address bar under the tabs taking up most of the width of the screen with one icon to the right of it. I still do not like the back and refresh and being forced into their locations and would like to be able to drag and drop them where I want (including where I have the other Icons).

I would like to be able to put the address bar where I want, including on the menu bar.

I would also like the ability to change the spacing in toolbars, I have quite a thick line under the bookmarks and too much space above them, overall this wastes screen estate.

In future can you PLEASE respect your users by doing the following:

The performance of the browser has improved, it is snappier but memory management is still an issue.

It seems to have a higher capacity before it crashes (from 1.6gb in old version to 2.4gb in new version) but it seems to use more memory so I am not really able to do more. I have 8gb of ram so I would like ot see it able to use 3 to 4gb if it is available.

This version does crash more often, it seems that some webpages leak memory and it gets to a point where is just blows. What it does do better is recover memory when you close tabs, it is not perfect but an improvement all the same.

I am still seriously pissed off with the way this was implemented and all of the issues I raised in my OP still stand. What I want from the Dev team is NOT more excuses but a commitment to not do this again and only implement Ui changes with roll back options for users.