Oracle to Sybase - a good move?

Any advice you could give me would be appreciated - I've just been offered a Sybase DBA/Design position: The package is good, but I would be swapping 5 years Unix, 3 years Oracle, and 2 years CASE skills for VMS, Sybase, and Logic Works, all of which I have had *no* experience of.

Does the jury consider this to be:

1. A good move to gain extra skills and become an "all round" Database expert. I'm told that it would be easy to move back to Oracle(or any other RDBMS) even after 5 years+ of Sybase because of past experience and general DBA/design ability.
2. A bad idea to move out of something that has major market share and that I know pretty well. I.e stick to what I know and can do well.

???

Any and all opinions will be gratefully received; I'm at my wit's end trying to decide!

--
Simon Holt --  System Designer/DBA
** My opinions are not nescessarily those of my employers **
Britannia Zinc Ltd. Bristol, UK. (+44) 0117 980 2510