Sylenth is a most excellent choice Dave. I don't think you can go wrong with that synth. It sounds amazing, pristine, tons of soundsets for it (1000's) and super light on resources. Only downside it is rather limited in modulation assigments and routings. There are a few 'better', atleast more modern sounding, synths out there, but none as light imo. I'd say Spire sounds more modern, but it doesn't have the sharpness of sylenth, hard to explain.
I'd say go for it
Hive by uhe is another one worth having a looking at, urs' take on sylenth, decent on its own, but still not a replacement imo.
Cheers