These are apples and oranges. Your $105 kit is commonly called the Lee Classic 4 hole turret press. The $71 one is the older style Lee Deluxe press with manual index. The conversion kit changes this $71 press into a four die press, but it still isn't the same as the Lee Classic press. The $76 Lee 4 Hole Turret Press with Auto Index, commonly called the Lee Deluxe 4 hole press is the closest relative to the $105 press. With the $76 Deluxe you DON'T need the conversion kit. All you need for a different caliber is another $13 turret and whatever dies you have.
I have the Lee Deluxe press and am very pleased with it. I only reload pistol, so I don't put stress on it. Some say that the cast aluminum is cheap and may be prone to breakage, which may be true if you're doing rifle rounds without lube. Common wisdom says get the Lee Classic over the Deluxe. If $$'s talk too loud, at least you know the Deluxe will work.
