Just yesterday I received the 540 FGZ II flash that I had pre ordered a while ago when they were first announced, and took some time this morning to check it out and compare it to the 540 version 1 flash that I already own.
I currently own Pentax K-5 classic, Q and Q7 bodies that I use with my 540FGZ 1's periodically so am somewhat familiar with the operation of those units.
Pentax has improved a few points in comparison to the previous version with the II series, namely:
- Weather sealing
- More compact size
- LED lamp that can functions as video light
- Better battery door operation
- Metal foot
- Easier setting of functions with simplified buttons
- Range of manual power down to 1/256 vs. old one only going to 1/64
Other changes include:
- Omission of AC and Sync ports
- Omission of catchlight panel, replaced by LED as catchlight function
- The soft case seems cheaper with a drawstring design
Overall performance of the new flash is not markedly better than the old 540, since the range and power are similar.
In use the pictures of my stuffed animal target were not different from using one flash or the other, with direct or bounced flash as well as wireless.
Setting menus for wireless and manual controls was simpler with the new unit, the old one has different buttons to set different options.
My opinion is that the changes in the 540FGZ II are not worth the substantial increase in price over the previous 540.
The changes in the 360FGZ II I do believe are significant over the old version of the 360, with the addition of swivel functionality, and all the features seen in the new 540FGZ II are available in the 360FGZ II. The manual is a dual purpose manual for both the 360 and 540 units, and there is no difference in what they can do or how settings are made, except for the range differences due to power of the flash.
Do you even need to go with a Pentax brand flash? If you prefer manual setting and use wireless third party units then I don't think so.
If you want the auto capabilities of PTTL with wireless capability then you might consider a Pentax flash and the 540FGZ version 1 may be all you need as long as you are careful with the battery door.
As far as the WR construction of these II versions, it really depends on your usage - for dusty or damp environments it may be worth it.
Regarding the video light function, it did help in some lights out testing that I did in movie mode, but it is not spectacularly bright.
A separate video light panel would be more useful, but it is nice for the convenience of having it if you need it in a pinch.
Here are some pictures of the new and old flashes with explanations where appropriate, taken with a Q7.
Since the resulting lighting of the new and old units was virtually identical I only show one picture of my stuffed animal model to show the catchlight function.
There was no noted differences in light output of the new and old units, or change in operation once they were set to match function.
Size comparisons. Note the missing AC and sync port.
The battery door.
Wide angle panel, note missing catchlight panel.
Catchlight function
Off

On
Cases
Metal foot