Capsule does allow crossfading between arts and applying legato to other arts, but SF can do all the rest better than the others.
Guess I have to disagree here...There's lots of good stuff to say about both OT and SF strings, but Capsule/Berlin Strings actually does - IMO - a number of things better than Spitfire (in addition to being able to add legato to all long artics).
Before looking at this list, remember the price differences between SFs Studio Strings and Berlin Strings.
Berlin generally has better legatos (all this is IMO of course)
Solo/mute/pan on all mics
AutoGain: if I select three mic faders and change the level of one of them, the other two are adjusted automatically, meaning that the combined out level of the mic package won't change.
Berlin Strings has a knob for legato volume which works really well.
One can "morph" between up to four different articulations in the multis
The Multis contain many longs with dynamic changes
You can disable on or two layers and Capsule will automatically spread the reminding layer(s) over the whole dynamic range.
CC remapping
5 mic positions in the core product (for V1)
Tons of parameters can be CC automated
Also - from the manual:
Niente: If enabled, the lowest dynamic setting (usually CC1 at 0 or key velocity at 0) will cause the instrument to be completely silent. Use this setting when using your instruments with a breath or wind controller.
Soft Low Layer: If checked, the lowest dynamic layer will first be increased in volume when controlling dynamics and only later the next layer will begin to fade in, allowing softer low dynamics.