Needless to say, heavy spoilers are ahead. Kurogane says:

The ending is so… inconclusive. Worst type of end in my opinion dammit. Urge to kill Kawamori seriously rising. It’s never revealed who Alto chooses and everyone just manages to survive and land happily on the planet. I just feel like my feelings have all been trampled over and thrown away like a used dirt rag. Oh man, I was at least expecting some deaths.

So, even worse than Macross Plus, which itself left a bad impression.

UPDATE: DarkMirage was more verbose and circumspect, but it looks like he agrees. He used the word "cop-out", even.