Mill Max sockets 0305 - budget, good if you have enough room between the PCB and the case, easier than 7305 to solder
Mill Max sockets 7305 - more expensive than 0305, good if you don't have a lot of room between your PCB and the case, more difficult than 0305 to solder.
Holtite - more expensive than 7305, good if you don't have a lot of room between your PCB and the case, no need to be soldered, but more difficult than 7305 if decided to be soldered.
They come in the same lengths as 7305's and 0305's, but also a new in-between length (3.3mm; roughly the same length as a switch pin). The lip is also thinner than 7305 (0.25mm vs 7305's 0.36mm), allowing the switch to sit closer to the PCB.
Unfortunately, even the non-gold version of 3305 is slightly more expensive than 7305.
Sadek Baroudi released his VIK standard, which is a set of specifications and guidelines for interfacing between printed circuit boards, e.g. a main keyboard PCB and a module that supports specific features.
