Is there any compelling reason a programmer would host on a shared platform versus just having a VPS account somewhere?
Advantage Shared Hosting
Disadvantages Shared Hosting
Personally I think: run on a good shared account as long as possible, then switch to dedicated if it no longer goes on the shared platform unless the thing you are runnning can be confined on VPS. (such as : development environment that needs own server stuff).
A Shared platform frees you from responsibility for the OS. not having to apply OS patches, not having to pay for software licences for the installed software, anti-virus, firewalls, backups are all your providers responsibility.
Now the flip side to this is that living on a shared server means your use of the server has to be compatible with the other hosted sites on that server. You cannot be using major CPU cycles, large numbers of simultaneous users. etc.
You can go for a virtual private server, but I would be asking questions about what it was you were actually getting for your money. A virtual machine might believe it has 2 fast CPU's, lots of memory and plenty of I/O bandwidth to the disks, but if they are running 20 VM's on the one server, all of these resources are going to be compromised. insist on acceptable performance guarantees.
For that serious product, nothing beats dedicated servers. Even if you run VMWare on it and host your own virtual server farm. At least you know you have the hardware resourced available that you have paid for. you have the control you want. You just need the expertise to manage the servers when they are in an Internet exposed position.
It's a simple cost + feature balance:
You really need to determine how much you want to spend, how much you can responsibly manage yourself, and what features you need.