For a custom color, you would likely have to get it annodized by a private shop. Look around here on pbn and you can find several people who have anno samples that you can choose from or you can make you own.
For efficiency, I would say they are about equal, but would give the edge to the Geo3.
Accuracy is all out the quality of paint you are using and how well you match the bore of the barrel to the paint. With the luxe, you can get different inserts to go into the barrel and change them when you need to (freak inserts). With the Geo, it comes stock with a .689 bore, which is a good standard size, but you would either have to get the boost kit from PE or get another full barrel kit.
Both will have the same firing modes. The geo will be easier to switch modes and adjust settings since it has the LCD screen.
Price is about the same. New, the luxe is about 250 more than the geo. Used they are about the same.
Looks: All preference and up to you. This goes along with the feel of the marker. Personally, I don't like how long the luxe feels and much prefer the compact form of the geo. Hold each one and then you decide.
Maintenance: The geo will be slightly more reliable as it is a simpler design. Both will have the same maintenance though since they are booth spools. Just relube the bolt and orings every time before you play. Read the manual about when you need to do maintenance on the reg.
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