For a free Arp Solina style string plugin, I'm not sure you can beat this. I have used it in a bunch of my tracks and it sits nicely in a mix. That is really the true test of any plugin for me whether free or purchased is how well it gels in the mix and context of a song. The interface is pretty minimal, but you get what you need. You get three built in effects - delay, a vibrato and an ensemble. The two modulation fx really help give various string patches that swirly/watery quality that just sounds so nice. You get a pretty decent amp and filter section, and the ability to adjust the stereo delay effect level, feedback, input feed to the delay, as well as the delay time. There is also an octave select which is nice - I think most DAW software usually has a little midi plugin to shift the octave up or down, but nice that they added this.
You get 40 patches with Algo String Synth, and they cover pretty much anything you might need for this type of synth. You may need to tweak the attack or release on some patches to fit your track or style but there are plenty of variations here to get you going in the right direction.
I use this plugin in Ableton Live and it runs really good on my dual core dell optiplex. Never had any issues with it at all. There really isn't documentation that I know of, but it's so simple to use that a user guide really doesn't seem necessary. I never had a need for Customer Support - this plugin is super simple. If you've used other VST synth plugins and understand some basic things about synthesizers in general, this is a walk in the park.
I like vst synth plugins that play nice with my cpu, sound good in a mix, and don't get in the way with a lot of silly and useless knobs. So I really dig this plugin for that reason - you drop it into a track and it sounds great. I get to focus on writing music and not fiddling with a bunch of different controls trying to get a good sound.
It's a free plugin, so again i don't think you can go wrong here.