@Colliam7 In brief, but feel free to PM me and I'll give you (or anyone) lots more detail rather than jamming up this thread.
Brightness and readability - no problem, equal to or slightly better than the Perdix. I use the graphic display, so I can glance at the position of teh display rather than read the data - much like an SPG where all you're interested in for the most part is roughly where the needle is pointing.
The menus and being able to configure pages of info (NDL, GAS, Compass, timer etc) and havign the ability to choose which additional data to display on each page within the 3 areas is a bonus for customising it around the way you dive.
You can use the cable (or bluetooth ) to download data. Shearwater bluetooth doesn't' work on Win 7 so I'm left with uploading to the cloud via a mobile device and then back to my computer that way
The Steel (not core) will get Buhlmann as an optional algorithm at next firmware update (supposed to be Q3/4 this year). I don't know how that will be implemented
Fused RGBM is just as liberal as Buhlmann - I completed 48 repetitive dives over 12 days recently running P-2 on the Suunto and 45/95 on Perdix and didn't have time issues with either (no more than 5-6 mins deco occasionally after being deep)
Negative, you need to set it up and adjust the layouts on a computer, so if you realise you made a mistake in data presentation you're stuck with it unit you can plug it in
Silly water sensor - in high humidity plus diving in salt you need to make sure the sensor is dry post dive otherwise the computer can stay switch on - I've bitched at Suunto to give an option to either disable it of give me a sleep function I can activate from the menus.
Suunto will lock you out if you exceed a deco ceiling by 3mins - never happend to me.