Good Luck,
Personally, with over 4000 helo hours I loved flying them but they are just not a huge transport industry like the tubes and therefore command a lower lifestyle and wage.
Looking at the difference between the two I would always go for the helo for a sense of satisfaction of a piloting job well done, especially in difficult situations (SAR pilots will understand well!), an aircraft that needs to be physically flown and the thrill of flying, landing and operating from unprepared and unusual locations.
However the flip side is a reduced training cost (approx 1/3 to 1/2), the more regulated flying hours regeime, positive rostering and the ability to live, just about, where you want dependant on which airline you fly for.
If you then have a helo licence and rating, especially a CPL(H) or above, you will find that there are companies that are crying out for casual pilots on an ad hoc basis. Check that your company allows external flying though as this will impact on your max flying per year, with many companies pushing v. close to the 900 barrier. Also many, mine included, frown upon personal flying for renumeration, so beware.
Good luck
