LA Scoring Strings is fantastic for legato and portamento lines.
Really nice Div sections as well.

I have a rack-mount Creation Station from Sweetwater Sound.  8-core processor, 12 GBs RAM, running Sonar X1 in 64-bit under Windows 7.  My system specs well exceed the EastWest requirements.  Problems:

1-There are too many samples with similar and cryptic names that are all controlled in different ways (e.g., use Mod Wheel for one, speed for another, velocity for another...).  Someones the Mod Wheel controls vibrato, sometimes it controls volume and vibrato, sometimes veoldicty controls volumes, sometimes it controls sustain.  Sometimes you use CC7, sometimes CC1, sometimes CC11, etc.  Add into this that portamento may be controlled by speed or by velocity, or by a combination, or may not exist at all.  It is all too confusing.
2-Samples take a ridiculously long time to load.  Then if you decide you need a different one, you start over.  Each articulation requires loading a different sample.
3-Notes drop out a lot—like a synth that is running out of voices.  When this happens, the CPU use is low (like 20% or less) and the memory use is less than 4 GBs out of the 12GBs available.   And note that I am NOT using the samples in the folder called POWERFUL SYSTEM samples.

I got on the EastWest forum, explained this, and just asked: which is the best sample for a legato sound with vibrato controlled by the mod wheel?  The thread is long and confused things more,
The keyswitch samples are easy to use and sound good but are not legato.
I am not bashing the product—it can sound great, but the performance is poor, and the manual and videos need to match what the user sees on the screen more closely.

VSL is way easier and more efficient, though admittedly without all the options of Hollywood.

Update: Although the issues in my post above stand, some users on the Hollywood forum have kindly assisted.  The post by user Crown gives some on a legato patch (for those that use Hollywood):

http://www.soundsonline-forums.com/showthread.php?t=43049

Personal note: I used to love Mellotrons, then bought an ARP String Ensemble, then various synths, so I am happy to live in a world with all these orchestration choices.

Hey Konradh,

I don't have Hollywood Strings,  but I have had other libraries with similar issues.  I could not get Cinematic Strings 2.0 to stop dropping out until i raised the buffer inside Kontakt for individual patches.  It comes from the factory set at 60mb.  I more than doubled that and everything started working fine.

Also in Kontakt if you load a patch and resave it over itself it will load quicker.  I have taken to loading an instrument,  tweak it so it responds to midi data the way I'd like,  then save it with a revised name so i don't mess things up.  Your patches will then load quicker....(I Know...PITA!) 
 
So i don't know if you are using Kontakt or some other software to load into Sonar, but perhaps that is where your issues are.

That samples take time to load is very true. On the other hand, one must say that the samples are quite huge, so there it is. That's where SSD HDs are nice.

Like Jimbo said, there is a setting in PLAY that allows you to set streaming buffers. The more you load into RAM the better it will play, at the obvious cost of RAM load.

This depends on how many instruments you load - but try to keep for e.g. string samples in one instance of PLAY. That way instruments that share the same samples will only load once what's in common between the two or more different instruments.

Also, I got some shocked reactions on this forum when I talk about my latency settings - the buffer in my RME settings is set to 1024 which translates to 54.1ms roundtrip in X1. To be honest I got used to it so much that I barely notice.

My point being - when using heavy samples, you do need to be kind to your computer and increase latency.

As for different ways to articulate various patches, yes I agree. It's not that uniform. Even the KSes between the same families are not the same (why not keep all the pizzicato KS on F0 or F6 depending on the register, for example? Beats me.)

But in the end all it takes is some getting used to. And the names do hint at what the patch does - like DxF is Dynamics Cross Fade, MOD would use the modwheel, etc...

Apologies if I'm saying things you already know about. But I do hope you solve this issue coz like you said, HS is a great-sounding library.