Executive Meddling - The story was originally written as a feature length movie, but the studio was unwilling to risk the production budget for a theatrical release straight off, so it was re-edited into a four episode OVA, with the theatrical version edited to be closer to the original screenplay following a year later.
This lead to the removeal of a post-sex scene between Lucy and Isamu (and the only boob shot of the movie), some minor scene editing/shuffling, and some music changes, but nothing extensive.
The English dub gets hilarious when you realize that it's Walter White facing off against Batou. Guess Heisenberg got into trouble with Section 9, huh? Come to think of it, Dyson was a scientist too...
Show Hayami / Steve Blum - Playing the small role of Marj Gueldoa, Myung's manager who might possibly be in love with, and manipulates Sharon so she can get sort-of life..
Mako Hyodo / Akino Arai - Both Sharon Apple's speaking and singing voices, respectively.
No Export for You - Compared to the rest of the franchise from which it comes, this is a rare exception, with retail DVDs being readily available and the movie version being a staple of the Sci-Fi Channel's anime block. By all indications, the only reason it got through the infamous "Macross legal snarls" surrounding Tatsunoko, Harmony Gold, Studio Nue/Satelight and Big West and was released was due to absolutely overwhelming pressure for release from basically every other corner of the industry; fans wanting a legitimate release in an era just before digital downloads were prevalent, critics wanting another excellent production to be released internationally, and similarly other animation distributors wanting an excellent product out strengthening the marketplace rather than being held back and producing no profit at all for anyone. It helped that at the time Manga Entertainemnt was able to snap it up, Harmony Gold was in chaos after a staff-hunting raid by Haim Saban, and nobody was paying attention to make a legal challenge; once they did realize what happened, the above kicked in to make challenging it far too dicey a proposition from a PR perspective.
It also helps Macross Plus has very few vocal songs and most of the themes are instrumentals, compared with later series.
What Could Have Been: According to Animaze, they wanted to get Bryan Cranston to dub the movie version in English, but trashed plans for it since at the time, he was involved in the production of Saving Private Ryan.