I am not GGL and never have been, but I can comment about ULTI and HON.

HON is still the "best" for some of the benefits it offers, especially access to First Class Lounges at the hubs, limo service to open stands, booking guarantee for paid and award tickets, upgrade vouchers, they make sure that you don't miss your connection at hubs. BUT (a very big but): HON is a shadow of its former self. The call centre is rubbish now, upgrade vouchers almost impossible to use, your benefits like free seat and luggage do not work on the lowest fares, etc. And worst of all, and this is the biggest "but": you will need to fly Lufthansa, Swiss, Austrian, Brussels. And those REALLY are totally faded glory. The hard and soft product on Lufthansa is outright bad, their Business cabin totally outdated with 2-2-2 configuration and only slowly being refurbished to something where they have 12 different types of seats, etc. Operational reliability is not good at all. Fares are high and they love putting all kinds of fees and restrictions on them. In a nutshell: the status is attractive albeit not as attractive as it used to be, the flying that it takes to get it is really painful.

ULTI as a status has become MUCH MUCH better than at its launch, but still doesn't many of the benefits of HON. Lounges are nothing special, you are still stuck on the bus with other people, no booking guarantee. Delivery of soft benefits is sometimes quite random (but some people don't care whether they get their personal greeting or not). Call centre is generally excellent. ULTI is easier to earn, because Economy flights count as well, as well as any AF- or KL-coded flight operated by another airline. And it's more pleasant. Air France, far from being an "excellent" airline, is a good airline and definitely better than any of the Lufthansa Group companies. Cannot comment about KLM though.

One final thing to consider: where do you connect. Zurich and Munich are very pleasant and organised for transfers, clearly the best among them. Paris CDG for intra-Skyteam is ok-ayish now - but has one big advantage, a dedicated ULTI lane at immigration when entering the Schengen zone. Frankfurt, nope, not great. Amsterdam I cannot comment.

Hope that helps a bit.