OE Style Hydraulic Roller Lifter Question

My 91 roller block LA 360 is at the machine shop right now. The block is cast for roller lifters, but I don't have the spider or bolts to hold it down. The engine will be a 408 and is being built for a Saturday night cruiser, not a race car. We are going to use a hydraulic roller camshaft from Comp (still undecided which one at this point). The Comp Pro Magnum lifters are $530 from Summit.

Is there any reason to spend that kind of money on "retro-fit" lifters when I can buy replacement hydraulic roller lifters for around $120 set? I realize that I will have to buy the spider also, but that's only another $30. Is there that much difference between a name brand replacement (Melling or Elgin) and the "Retro-fit" hydraulic lifters?

Thanks in advance for any help!