Inferno looks cool.
However, to actually use it, there are some requirements that have to
be met and some that should.
An Inferno network cannot exist in a vacuum.  The workbench has to
provide for dealing with the outside world.  And it should make the
user feel comfortable by providing some help when coming from
UNIX/Linux.

I Showstoppers: 

These are applications Inferno/Plan 9 will not survive
without because they are simply necessary to get some work done.

Ia Webbrowser. 
I hate the web.  I really hate it as much as I loved it when I stumbled
upon it in the 90s.  But not being able to use the crap out there with
it's Javascript and Flash and all these hyped junk tech, means not 
being able to survive in a lot of activities ranging from university 
courses through job applications to finding the bus-stop.

Ib SSH.
Of course connecting a terminal to a remote host breaks the metaphor
of Plan 9 and introduces just the same confusion that UNIX and the
DOS-Derivates suffer from.  However, these hosts are out there.
And we have to work on them.  I simply have to login to a couple Linux
and UNIX hosted shells because they are the workplaces I am told to
use.  Silently running Inferno in userspace everywhere actually is an
option.  But this might mean fighting firewalls and workplace policies.
Not the very best way to become the boss' best man.
Therefore we have a very simple conclusion here: No SSH -> no
transition to Plan 9.

Ic PDF.
Yes, this hurts almost as much as the web browser.  But it is the 
de-facto standard for documentation.  No good PDF viewer, no
transition.

Id DOCUMENTATION.
Capital letters.  The current state of affairs is depressing.
Documentation like the man page for fs is written for anybody but a
user who needs it.  It might be faster to explore fs' usage by
brute-forcing through all possible combinations of command-line
executions within, say, a length of 24 characters, than to understand
what the hell the fs (1) man page is trying to teach us.
BTW, is it just me, or is it really that ironic to populate /doc with
pdfs when there is no pdf viewer application in the system?

II Helpers:

These are applications and components that are not necessary for
survival but would make users feel better and provide a somewhat smooth
transition.

IIa VI.
Vi haters scream in agony.  But I actually got used to it and even
scrapped vim lately to nvi.  Once you are accustomed to the screen
terminal approach it's pretty simple while powerful.  Plan 9 has ed.
Ok.  Ed plus wm/shell, which is more of an editor window than a terminal
emulation, might provide everything vi does - if someone has an easy
solution to get line numbers on the screen.  And if, just in case, this
Plan 9 ed really resembles UNIX ed.

IIb Printer Support.
Postscript printers are very expensive and sometimes hard to get if
you are just a common customer and not Big Company LTD. 
Plus all those printing devices out there are already there and they
have to be used.  Of course, with Inferno as an hosted OS, one can use
existing print servers and desktop systems.  But this is not what one
wants when switching the Operating System.

IIc Public Namespace.
The file system approach of Plan 9 is superior.  And mounting/binding
other name spaces like SMB, FTP, WebDAV and so on delivers a good
outlook on what might be possible.  But what about mounting public styx
services? I found some software for Inferno - I have to resort to
Mercurial on the host OS to get it.  Mercurial on Inferno does NOT
solve the issue.  Mounting the remote software directory with full
encryption and authentification into the "local" file system would
solve the issue.  Someone wants to publish a file? Why use web-based
directories that are dumb terminal front-ends to revision-controlled
file-system-based databases on UNIX hosts? Why not cp it to a
directory that is being exported to the world?

IId Documentation - HOWTO.
The single one feature that made Linux adoptable to many young
computer users and built it's world domination is a bucket full of
HOWTOs and FAQs.  HOWTO compile a kernel.  HOWTO install Sendmail.  HOWTO
install a FTP server.  HOWTO install a LPD.  HOWTO get a decent mouse
support.  This documentaton was not written with specs or software in
mind.  It was task-focused.  It taught how to get a job done without
requiring expert knowledge of the system.
Things I'd like with Inferno: HOWTO use an existing print server.
HOWTO connect to a SSH account on a UNIX host.  HOWTO use that fXcking
fs tool to actually FIND something.  HOWTO find and install new and
exciting software for my Plan 9 cyberspace adventure.  HOWTO get Inferno
accept the '^' (caret) on my computer so I can actually start working
with the shell.

III Killer Applications:
When trying out new tech you always have your boss, other users or
that mean sarcastic guy in your head ask the same questions:
Why should I do this? Is it worth the effort? What do I get in return?
If there is a really convincing answer to these questions, it's a
killer app.  Microsoft Windows had Excel and Word.  Later came Corel
Draw to help.  DOS had Wordstar, than Borland Turbopascal, BASIC, 
Windows.  OS/2 Warp had, well, the workplace shell but almost no affordable
apps.  That's how it died slowly and painfully.  Linux had the GNU suite
and all the internet deamons together with great documentation.
WindowsNT had being Windows without the crashes.
What do Plan 9 systems have?

IIIa The File System.
The Plan 9 file system approach actually delivers what the Gopherspace
promised.  This is the simple-to-use global file system where you can
sort, announce, find, research, use and restrict all the
databases, documents and information-focused services in the world.
If services which are provided using a outdated and quite often
ill-designed WWW approach are provided as mountable styx resources
the Plan 9 on a users box at home extends into cyberspace.  And in this
scenario there are no metaphoric divides between file spaces and
client-server architectures, terminal-host environments and
chaotic workstation jungles.  It's all one file system and it's
astonishingly simply to use.  It's what gopher wanted to be. 

IIIb Inferno hosted OS.
No need to throw the legacy desktop-server environment out the window.
Inferno can help with a smooth enrichment of exising installations,
later replacing them.

IIIc High Quality Software.
It's already there.  It's just a bit weird having to resort to crappy
documentation or (even good) apps from the host OS when you want to use
this software...

Let's see what the future brings.  It's promising.  Plan 9 might work.