RE: Accounting Vendors

And if you have an infrastructure based on 5250 terminals, which could
include twinax cabling and handhelds that talk 5250, the expense to
replace with PCs/thin clients makes the ROI case much harder.

We're not talking a new app.  We're talking a new app + upgraded server
capacity to deliver it + potentially new client workstations +
potentially a faster network to handle the extra bandwidth + user
training on the new devices + user training on the changes to the app +
added support costs because the new environment is more complex.  That
new server may take more space in the data center as well and may
trigger upgrades to the data center's HVAC & UPS.  If you're replacing
twinax, don't forget the switches & other LAN Devices you'll need.  And
you'll probably be buying a round of new printers as well.

And if converting to PCs, add in the higher ongoing costs of using and
maintaining the PCs.  Security software like AV, admin for deploying
updates, higher electric & AC bills if anything but laptops are used,
etc.  Don't forget to allow for the loss of productivity due to users
waiting on machine reboots.  Even though Windows is far better than it
was just a few years ago, it's still nowhere near as reliable or as
close to instant-on as a tube.

Now, there may be other reasons to deploy PCs/thin clients that make the
case more convincing, and that's fine.  The sum total may well make it a
no brainer to go GUI.  But if your existing infrastructure is
terminal-based, getting to GUI is not cheap.