Does this mean that you will use freed time on tabsrmm development? Or just spare it on other problems in RL?

But what do you suggest as an alternative? Using clist_classic or do you recommend to use clist_modern? Or do you think that you will support clist_nicer enough in the future that people can count on it?

I would say, use whatever you want and whatever fits your needs best.

Clist nicer is pretty stable as of now. There are no serious bugs (at least no crash or similar problems which can really hurt) and some of the minor bugs may be fixed as long as it isn't too much work and doesn't make it necessary to rewrite bigger parts of the plugin to get a problem fixed (one example would be the configureable menu ordering system - that probably won't ever be fully fixed, because that's not possible without rewriting it completely).

clist_nicer is a good alternative to clist_classic or clist_mw. It has more features and decent skinning, but cannot do all the spectacular effects clist_modern can do. On the other hand - its faster

So, - from the user's point of view - is it worthwhile to continue using clist_nicer?

I think it is. It's not completely dead. There will be a new release every once in a while to fix some small issues and to improve a few things. Basically, clist_nicer is the contact list I use for my own needs and when I find something which really disturbs me then I will most likely change it. But these changes will only be small, I don't need any new feature in a clist and that's why people should consider clist_nicer+ "feature complete" and not expect any new and exciting stuff