I just got a call from my former employer, they want me back to run one of the mill locations. now Im really torn, as the employer I'm with really wants to keep me.

Details:

TELUS ITI
Contract -Full time pending in January (3 contract extensions)
#9 public company in Canada on contract for #40 company in Canada
Great Learning opportunity
opprotunity for advancement
Desktop Tier 2 On Site Service
platinum plated benefits plan (if i ever get full time)
Management position, Tier 1 is Union (its ugly to)
Microsoft shop
The Contract Liaison is a jerk and regularly goes out of his way to piss me off
I'm feeling a little strung along on the contracts, but apparently its just the way TELUS is due to the union.

Millar Western Forest Products
Full time
Private company, small/medium
strongly affected by commodities in lumber and pulp (why I was let go)
learning opportunity as needed
I will be calling all of the shots for the Pulp and Lumber mills in whitecourt (desktop, server, network, and some GIS)
gold plated benefits plan
Millar is non union.
Best of Breed Shop bit of everything and it all works together.

both will match wages.

I really enjoyed working at Millar, as I reported directly to the Manager and Director. I had the freedom to do what needed to be done, and had direct hands on exposure to everything. I am critical to decision making as I plan and implement all new networks, servers, and desktop upgrades. I will have to move to Whitecourt.

I like working for TLEUS, but it is a helpdesk, the same problems keep coming up, but I am "the golden boy". other support teams refer to me. I am the Team Lead appointee. I have no influence in decision making. I will not have to relocate.

What should I do?