You must have some incredible Cu's not to have to heal them, or maybe I'm just attacking too much at once or something. Cause my main trained Cu is a 3.9 and he isn't godlike, he needs to be taken care of and healed just like any other pet. I have a bonded 4.3 I took out the other day to start training while I tried to tame swamp dragons and the swamp creatures made short work of him. LOL. Training accounts for quite a bit on a Cu...
I take my GD out when I'm feeling lazy as it can take more hits before requiring intervention. Or when doing things which require a "tank" and people are too squishy.
Most of my cu sidhe have the same skills and stats as the day I got them. I've trained up a couple of them, but honestly I just don't care for them. The ones that are trained do still require vetting at times, depending on what we're hunting. I like using them in the Abyss with stuff that has an area effect when I get tired of always running out of mana from casting heal spells from a distance on a greater dragon or a hiryu. (My bard tamers have low meditation skill and I'm too cheap to redo their suits to try to max out MR and LMC.)
When the cu sidhe were introduced, I really wasn't all that impressed with what happened with them. They are definitely useful in some situations. But, like GDs today, I think people tended (note my use of the past tense here, please!) to use them in every possible situation and because they could heal themselves, many of the people I saw (including one particular guildmate who no longer plays) seemed to think the darn things walked on water or something. That was before we got things like crimson dragons, slashers, etc., etc. Think more along the lines of what we had to hunt in the year or two after the ML expansion and maybe you'll understand what I'm saying. Outside of doing peerless back then, many of the tamers I saw using cu sidhe were barely lifting a finger to help their pet. And those are probably people who don't play anymore because they got too bored with the game.
If you're still playing UO today, what I said probably doesn't apply to you, so please quit getting your feathers ruffled over something I stated was my own opinion and that doesn't count for diddly! They're just not my favorite pets for many reasons and that is why I've never felt compelled to make my tamers elves to go tame them. If I really want one, I just bug a guildmate who does like to tame them. I try to have one good one for each tamer and some of them now have two or three because that guildmate fiendishly manages to find hued ones in colors I can't resist, even though he knows they aren't my favorite pets. I swear he does it on purpose. Maybe he thinks some day I'll finally start training them and fall in love with them.
And by the way, do you still want some of those hued hiryus on Sonoma, JD?