Decision to make?

I have been working in the iseries market for 10 years.  I have read the
discussion thread that happened a few weeks ago here and found it very
intersting, some insight from you guys would be appreciated.

What am I?  I am an average and yet enthusiastic programmer, not overly
aggressive, not great at office politics.  I cant get reimbursed for
training on the iseries or new skill sets so have taken classes/conferences
on my own.

My current position is at a good organizaiton in a support role with some
programming in RPG.  I have expanded my skill set with some knowledge of sql
server and .net.  I am very busy with my day to day activities and have not
had time to really get in depth in these new areas.  I applied for a
Sr.RPGposition at a different firm in the area and they did not want
to pay more
then what I am making, so I didnt take it.  Im not terribly happy at my
current position due to the politics and certain bosses are self-cenetered
and difficult.  I do seemingly have job stability/security.

A new opportunity has come up with a similar type of organization to my
current one that requires someone with sql server and .net plus service
skills.  They like me even though I do not have a full backgrand in the
specific skill set.  They claim they have not been able to find anyone they
like as much.  The offer will be around 5% more than what i make now,
similar benefits.

What would you do?  Do I leave the iseries behind?  Do I try to renegotiate
with my current employer to expand/change my day to day activities, possible
money adjustemnt from them?