Both software packages have their advantages and disadvantages. I have used FactoryTalk View ME very extensively, FactoryTalk View SE on a few projects, and Ignition only sparingly.
When the software choice is mine, I will try to use Ignition in the future, for several reasons.
1. Installation is significantly simpler and faster.
2. Stability is impressively better. I'm including both the core components ability to run and stay running, and the speed and volume at which patches and problems are revealed and rolled out.
3. SQL database integration in Ignition is fantastic. I don't have to convert or export or otherwise mess with my data; it's all available in SQL. While RA has connectivity to SQL, the legacy database and log formats are big headaches (and the Machine Edition stuff is proprietary and disappointing).
4. Vector graphics are very nice. It takes some work to make things line up and scale to different screens in a meaningful way (a fixed-pixel display is simpler !) but it's worth the effort. RA's launch of PV5000 next year will narrow this advantage a little at the low end.
5. Client licensing issues don't exist; the Web Launch is almost trivial to configure.
6. It's hugely powerful. I can do nearly anything in Ignition, while I frequently found frustrating limitations in FactoryTalk View (especially ME) in terms of which aspects of an object I had programmatic access to.
7. The trending and database access objects are head and shoulders above everything else I have used.
FactoryTalk View does have some advantages, especially now that it's reasonably stable. Versions 3 and 4 were not pleasant to live through, but that's in the past now. Those responsible have been sacked.
FTView is very well integrated with ControlLogix. The RSLinx Enterprise Tag Browser and Direct Referencing are by far the fastest and easiest way to get data from ControlLogix to an HMI. RA has the keys to the box of secrets for ControlLogix communication optimization, and they make it work well, especially for fast trending.
Because it's a native Windows application, it mixes fairly well with other Windows applications, including Visual Basic. If I started tossing apples from my office, I could hit one Python programmer and one Linux guru but three Windows programmers.
FactoryTalk View ME runs on the rugged and reliable PanelView Plus hardware. I've seen a lot of touchscreen PCs and none of them are as sturdy as PV+ hardware.
FactoryTalk View has a significant user base, from which you can draw experienced contractors. While I admire Inductive Automation's skill and dedication, RA just hosted an open bar on the flight deck of an aircraft carrier during their annual software training event. There's some momentum there !
This week I'm on a customer site where we have a bunch of PanelView Plus and custom software doing heavy trending and high-integrity data logging. And I find myself wishing I could do it all over again with Ignition, because of the limitations on storage, speed, reporting and connectivity in FactoryTalk.