The middle is a tough place to be when it comes to luggage...
I've found that a $150-$200 bag (such as a TravelPro Crew series) will last longer than a $50-$75 bag (like a Ricardo or Samsonite from Costco), but not 3-4x longer. If you buy in the middle, you're buying the convenience of having to replace less often along with the fit & finish of a nicer bag while you're using it, but in most cases you're just not getting a bag for life. In some cases this sits fine with me, other times it doesn't.
What I've started to find (similar to Buster) is the best value comes from buying at the low-end of high-end (Victorinox, Eagle Creek, T-Tech, eBags house-brand, retired models of B&R, etc) when you can get an amazing deal... now you have the benefit of a truly well made bag (and often an associated bullet-proof warranty) along with a cash layout that you can stomach.
Back in the fall I came across this type of deal on an Eagle Creek ES2 Rolling Tote on Amazon for $30. Based on the build quality and the warranty, this bag (or whatever replaced it under warranty if it couldn't be repaired) would last me a lifetime... however, it was stolen from the trunk of a rental car in a parking garage and the deal was gone when I needed to replace it. I ended up going with a cheap Ciao bag from Costco, also $30, to replace it and now after only 3 trips I have a dented handle channel causing the handle to stick. Luckily in this case it did come from Costco, so I can get a replacement fairly easily. Still, it reiterated my point knowing what you need to buy/replace with enough foresight and quickly reacting when the amazing deals do come along is the way that works best for me when it comes to buying luggage. Luckily right now I have enough bags to chose from that, even if I lose one particular form factor to damage/theft/etc, I still have time to watch and wait for a great deal... even if I don't come across one in time, I still have something else that can fit the bill.