Ah... yeah, right. It's still an updated version from the X1 QC (pre "Expanded").
 
So newer (unless they owned Expanded) but no flyout.
 
The Frequency Analysis in the QC flyout is quite handy though so that'd be somehting to consider.
 
Sorry... I forgot the flyout did not come with Professional.
 
PS: I've been adressing what seems to be the original question. That would be that OP is happy with his current set of tools and is just making sure he can use them in Sonar Professional. Everything extra that comes with Platinum would be "extra" items.
 
So from X1 Producer to Professional = All current effects migrate to Professional plus they'd get the few extras that have been added since X1 that come with Professional (like the lesser AD2 package, TH2 Sonar, etc).
 
As far as certain premium Sonar FEATURES though (not plugins) I'm not sure if anything would be removed. I'd have to look at the list. For example I'm not sure if Audiosnap is included in Professional. I'd be more concerened about those types of Baked in features than the VST plugins.

From what I can see on the feature comparison list, the major differences are in the plugins.

Drum Replacer -- don't need it.
VocalSync -- don't need it.
Lounge Lizard -- don't need it. I'm a classical guy.
Strum Session -- don't need it.
TruePianos -- I have that in X1 Producer now.
Boutique Suite stuff -- A lot of that is in X1 Producer.
ProChannel: PC4K is in X1, but it's the only thing. Professional has more than X1 here.
Loop Content:  I'm a classical guy.  Would never use someone else's content.
 
So, after analyzing all this... I'm thinking Professional is thew way to go. 
 
Thoughts?
 
Karl

Yeah, you'll be fine. Just know that you gotta keep your current installation of X1 installed to keep those plugins. If you end up in a situation where you have to uninstall X1 or you move to a new machine you'll lose those old plugs. In which case you can just either entirely reinstall X1 or do an Advanced install and just install the plugs/components you need from your X1 discs/downloads.
 
Also if you DO find out later on that maybe something crucial isn't working or appearing in Professional then just contact Cake support and they'll help migrate your upgrade to the desired version without paying the full price (just the balance difference).
 
Be aware though that some of the older plugs were dropped for a reason (stability issues) so maybe they won't work as well in Professional as they did in X1. I haven't experienced that much with older plugs (X1 Pro vs Splat) but aside from curious oddball experiments I mostly stick to some very specific plugs in my general usage.
 
Seriously... you'll likely be okay with Pro. It's a good value choice actually (at the full upgrade prices) if you don't need the extra doohickeys.
 
BTW... I keep all my old versions installed partially out of laziness but mostly because I like having the older versions around in the unlikely event maybe Splat doesn't do something quite as well... and I also like to have them there in case I want to research some old method of doing something versus the new ways.
 
That actually brings up another point. You're gonna likely have some "update shock" due to the newer Take Lanes and Comping Mode/Comp Tool as well as some changes to the interface.
 
Of course those changes are thoroughly documented but if you run into trouble just ask here.
 
Cheers.