I think I'm right in saying that the Tiger is a Centaur with fin keel? In which case, it will probably sail better than your Eventide. On the other hand, you'll loose the shallow draft/drying out capability.

If its a maintenance issue, then you may experience a net benefit (i.e. reduction in time spent) although any elderly Westerly is likely to need a lot of cosmetic attention, with possibly some structural challenges as well (keel bolts and headlinings come immediately to mind) For what its worth, I always find one of the real joys of a wooden boat is that no matter how tired-looking it gets, a modest amount of work will bring it back to looking as good as new. On a GRP boat, however, it is very hard to rejuvenate the looks once the gelcoat wears and fades.

Again another personal view, the Eventide has a timeless elegance about it which on the East coast particularly looks absolutely 'right'. The Tiger, on the other hand, although not an unattractive boat has the firm stylistic stamp of the late '60s/early '70s.