Hi,
This reply is probably too late for any decision that you are making.
I use the Clas Olson version of the Fine Offset, which works fine with WeatherCat. The temperature sensor is not well shielded and so definitely reads a bit high where I have it situated. As it doesn't update very frequently, the wind speed readings probably miss many gusts (but in my situation, I haven't really got a nice exposed place for the anemometer in any case). Assuming you can get the model for a good price, I would say it is a great introduction. I'd love to have a Davis, but that is a major investment and probably overkill for the situation in my garden.
I've had the Clas Olson for almost a year now - don't know how well it will survive in the long term, but as it was so cheap when I bought it (only about ?50 as opposed to the "normal" price of around ?100), it is almost disposable. I have seen the same model in other branding being sold for anything up to ?150 in the UK.