Is the final rank of the shield device worth the cost?

Pretty much the title, is it worth 1000 certs?

Well I bought it. It seems much larger and maybe a bit faster, not entirely sure though.

I do believe the last rank gives a larger increment, to range at least, than the previous ones. Can't remember specifically without checking though.

*EDIT* Wiki confirms a 1m increase in bubble's radius on last rank, instead of the 0.5m on previous ranks,

It is a rather noticeable difference on size and I believe it will take priority over any other lower tank ones since it is the highest rank. So I would say yes, especially if you play medic a lot.

Depends.
+ It guarantees that you will receive xp for any damaged ally in its AOE since the last rank has the highest priority, no more losing xp because someone has a better bubble.
+ It's a pretty big range boost.
- But it costs a lot, it took me quite a while to get enough xp to justify spending 1000 certs on it.

It's a good investment for players maining Medic class but not optimal for anyone else.

Mandatory if you play medic as your main class or if you want the ability to grind some certs in large infantry fights.

You need it! It will pay for itself in no time!!

A bit late, I've had it for a while now

At least it causes less FPS drops now.

Or so I hear - I haven't logged in since they changed it.

My FPS was never really affected by it so I can't say. However, I find it really annoying to figure out how large the field is.

Its not worth using UNLESS you have the last rank IMO.