I think I'm a fairly well-versed Android user -- there are now five devices in regular use in my house, and I've been using it since the original Droid came out. All except one is rooted, and most are running unofficial ROMs.
I've only heard of two of the alternative markets: GetJar and Amazon. I have them both installed on one device, largely to see if anything interesting comes along. So far, my opinion is that they are smaller and even less well laid out than Google Play.
I suspect doing an alternative market right -- with good search and categorization, suggestions made on some basis other than "current promotion", friendly to developers -- could be a lucrative proposition. I'm not seeing that now from any current vendor.
I've only heard of two of the alternative markets: GetJar and Amazon. I have them both installed on one device, largely to see if anything interesting comes along. So far, my opinion is that they are smaller and even less well laid out than Google Play.
I suspect doing an alternative market right -- with good search and categorization, suggestions made on some basis other than "current promotion", friendly to developers -- could be a lucrative proposition. I'm not seeing that now from any current vendor.