SMD vs. Through-hole components in high vibration environments

Less mass has to be better, and an SMD resistor has a lot less mass than thru-hole.

The only vibration (SAE J1455) SMT problems I've ever seen for common components are failures for large aluminum-electrolytics. The solution there is just to anchor them down with a gob of silicone.

An 0805 resistor will not fall off from pure vibration unless there is a tremendous amount of board warping going on (then it may fracture), or unless you are going to expose it to several thousand g routinely (in which case you have bigger things to worry about).

An 0805 resistor weighs about 4 milligrams, and the pound of force or so I just put on one (on a PCB on my desk) with my fingernail did nothing, so that's equivalent to about 113,000 times earth's gravity?

Are you up against twisting forces at all? Or just vibration? SMD component has a bit less mass, so for a given amount of vibration it'll put less stress on it's joints. On the other hand, the through-hole component won't care nearly as much if the board is flexing because it's got wire leads that should let it move around a bit.