I've extensively a/b the Nautilus line when moonlighting in stereo sales at a high end audio store
I prefer the 805 with a good sub to the 803 and 804
You hear too much of the cabinet resonances in the 803 and 804 which are not present in the 805.
speaker placement is critical
The 802 seemed to have the best balance of all
The 801 was slow and imprecise. The bass frequencies sounded a little bloated
just my opinions based on my own ears
I prefer the 805 with a good sub to the 803 and 804
You hear too much of the cabinet resonances in the 803 and 804 which are not present in the 805.
speaker placement is critical
The 802 seemed to have the best balance of all
The 801 was slow and imprecise. The bass frequencies sounded a little bloated
just my opinions based on my own ears