In the early years, mine were 80% metal. I sold off most of my collection for a charity project, which collapsed on me. I then began collecting/building armies anew. The second go-round I went for more plastic minis: less expensive, more of what I wanted was in plastic, than metal (see last paragraph, below).
I enjoyed the heft of metal mini's, for many years; I owned around six Prince August molds, and I cast a couple of hundred figures out of lead and their Model Metal -- plenty of weight in stands of three of these 25mm metal figures!
After I began collecting plastic minis, I grew accustomed to the (lack of) heft for my now 90% plastic armies. It really is what you grow accustomed to. This old dog, apparently, can learn a new trick. Figure sizes ("scale" is a very relative term, always useless, for fantasy, due to no standard sizes for creatures/non-Human races), but I found more plastic minis in the sizes that I wanted, so I went to plastic, because the figure sizes I wanted were only available in plastic. Cheers!