I'veused VW since 2005 (currently on v2012). Due to it's odd way of handling 3D I've only used it in plan view (except for cut & fill ops) - compared with Acad it's a step backwards, whereas SU is yards ahead of both in 3D. In a nutshell VW is like having a dog and barking yourself.
I do everything in 3D in SU and then export to VW for say plant counting or area calcs as VW has a good internal spreadsheet (but it's NOT excel and VERY poorly documented). VW does NOT work with Excel despite what you may be told about ODBC linking. I also send images out of SU for layup in VW. I've found SU LO to be too slow but it's probably my machine.
I also show my clients live 3D models and plans over the web from SU - I've tried screencasting VW but client screen output is black(screenleap works but not join.me). ASFAIK VW was written (in Pascal) for macs, and appearsto have been ported to Windows - it is also absolutely dependent on the version of Quicktime current @ time of release (this is not well-documented and can cause genuine stress). BEWARE of auto Quicktime updates.
My work is landscape architecture and planning (from courtyards to coalmines - mine reinstatement surfaces), so I work at both very small, and very large scales - VW in my experience doesn't perform very well when a site gets very large (>3km across) or very complex.
When I have more money I'll switch to Rhino3D plus a few of it's plugins - which will still make it only 1/2 the price of VW. Also Grasshopper is going to push my planting plans to new levels.
Some things:
can be very hard to achieve small email-size pdfs, due to inefficient data handling, and putting bitmap info outside the viewport into the file - the only solution is to tile and class each tile separately! That said I've just finished a complex planting joband seven sheets come to 6Mb and the client can zoom right in to small groups of plants, which I'm happy with.
VW has plugins but they are scarce with poor backward/forward compatibility). There are some great plugin writers. But the support https://techboard.vectorworks.net/ubbthreads.php?ubb=cfrm site is looking tired and visits seem to be falling off.
There are occasional scaling issues where metric/inch conversion seems to be going on seem to be the core problem -
The layer class idea is good in concept; but poorly implemented - Rhino has sub-layers, whereas VWs layers and classes are separate. Each layer can have it's own scale too and when you make a layer it can default to anything - be aware (lack of validation is almost a theme with VW)
Depending on your field there can be very few people using it seriously. In a word I'm still ambivalent - with landscape architecture and software you often have to take what comes.