Grace, I workout with heavy weights too, and I mean ~heavy~ but that Ada was too much for me.
The Jillian was just right. Just know that neither bag is a true shoulder bag. I can fit my Jillian on my shoulder in a pinch but it is close, up under my arm pit. But I love that bag and always feel great carrying her.
Good luck finding one at a great price. I think Ebay is the place to go if you are comfortable. You could email wowtag or Lninos, two great Ebay sellers, and ask if they have one or can get one for you, their prices are great, especially if you buy direct from them. I emailed them when I was on the hunt for mine, as I recall they discounted about 25-30% off retail. I happened to find mine from Rosenpetals here and got hers instead.