I've got analog synths, digital synths, and soft synths. My $40 Korg Monotron is more expressive than my $700 1997 Access Virus. But the Animoog iPad app trumps them both ($40, and I think I got it for $5 because I bought on the first day or something).
There's a reason nobody has ever cheapened the Stradivarius by creating new technology. The selling point is craftsmanship and good design. The 808's a work of art and it's always better to have the real thing, if you're serious about music. (I mean absolutely no offense, but it sounds like it's just a hobby to you.)
Speaking of iPads, there's a great simulation of a later-model Korg ER-1 drum machine availabe for iPad. It's called iElectribe. I love it, but I used to own an early version of the real thing, and it was just better. Context: I've owned many drum machines, even built a toy one for fun (the Bleep Drum, from Bleep Labs), and I'm learning to play the drums.