The HK boots are the only way you can get Orguss-1. No-one knows if Mangle has the US-rights from the old US-Renditions.
Rankings:
the good:
[*] video-quality: good. prolly ripped from the last Japan-R2 set.
[*] audio-quality: good stereo.
[*] price: very decent enough. Avg $30 to $40 for the boxset.
the bad:
[*] character-designs: Abundant Minmay/Misa clones.
[*] subtitling: horrible engrish. name-substitutions and name-mangling run amok as you progressed thru the whole series. However, it's a simple story so you can follow it even tho the grammar and name-spellings are pretty high on the weird-scale.
As for the Orguss-story, it's kinda interesting pilot-turned-wandering-gypsy-due-to-time/dimension-warp-disturbance. Interesting sci-fi plot but average story-delivery. Pretty much un-interesting and really boring unless you're so into 80's sci-fi anime. The only good mecha design is the Orguss itself, tho it's pretty much weak and ugly compared to Macross and Gundam mecha designs.
In contrast, the Orguss-2 OVA is a better story and has a better video animation production, as well as great character-designs improvement over the original Mikimoto-designs, i.e Orguss-1 Mikimoto-characters all look like Minmay/Misa clones. As others have stated, it only tries to un-necessarily and half-heartedly hook up with the original Orguss-1 in the last two episodes. Although it echoes Macross-II sequel-tradition, the closest story-parity/plot-relationship I can give it is prolly Gundam-MS-08th's relationship to MS-Gundam. Same people made Macross-II, Orguss-2, and Gundam MS-08th, anyway iirc. Very very much darker in tone and delivery than Orguss-1.