That's a great offer, when I got mine it was 75,000 bonus points. As for which is better, I have looked into that and still not sure I have it figured out but this is what I seem to find.I see there is a promo for PC Optimum MC of 100,000 bonus points until July 7th. Thinking of getting it just to use for No Frills, Superstore and Shoppers. Although I should do the math and see if it's better points wise to use this or my AM MC which gets 1 am for every $10. But the bonus is good, and no fee so not like I'm losing out on anything.
I use mine strictly at Shoppers. Every once in awhile they have a promotion for spend $50 get 20 X's the points and use your PC MC and get an additional 5000 points. I have had my MC since the first of the year and that offer has happened three times. Right there your ahead in value as the PC points are worth $5 plus the regular points PCMC gives you. With AM MC you get 5 AM's or the value of about .50 cents. Now when that offer is not around I still use my PCMC at shoppers as you get the regular offered bonus points and the MC gives me, on about a $50 shop PCMC gives me 776 points or about .77 cents. Here's an example of how it shows up
- PC Financial Earn
Thu • Jun 13
+388 pts - .
PC Financial Earn
Thu • Jun 13
+388 pts
All said and done, your getting 100,000 for getting the card ($100) and there are those bonuses every so often for using PCMC so even if you only use it at Shoppers, which is what I do, your way ahead of the numbers game. I will sometimes use it at Loblaws but only when there is an advantage. Hope this helps you.
With the tax it came to $90.38 The good news? 23 700 points earned! 

You might learn a few tricks over there as well, lots of people joined over the years thinking they'd never manage to earn enough to redeem for anything of any value and ended up snagging MANY tickets/flights/car rentals/hotels & merchandise as well. Even if you only focus on the big events you can still get some decent hauls.