I'm a big Sig fan and have enjoyed several of their kits over the past 25 years. I started with a Kadet Mrk. II and later continued with one of their quick build mustangs, an aquastar and owned a kougar that someone gave me for a little while. All are good plans. A few years I wanted something for my sons to get started in the hobby and was pleased to find the Sig Senioreta EP ARFs and now have two of them (one for each boy). It may have been a mistake but I couldn't bring myself to buy a big expensive block of foam. One of the best things about Sig kits are the instructions. I still have the instructions for my 25 year old Kadet. It is great reference for how to determine thrust lines, CG, incidence angle, pushrod geometry and other things. Much of this knowledge is omitted, or incorrectly assumed to be comon knowledge by other manufacturers.
Some new owners bought the company a few years ago and they are going through the lineup of models and adjusting the offerings to make the company stable fo the long term. I know this from speaking with some of the employees at the Toledo RC show the past two years. Unfortunately this means that some of the offerings are temporarily or permanently unavailable. Some of their Asian build ARFs have been removed and will be replaced. Unfortunately these designs have gone Grey Market and can be bought through other suppliers. Even though the quality of these grey market models is not the best I'm sure this hurts Sig. Some of their supplies and offerings will not come back (their covering, engines, and certain models) but they should be building their line of offerings back up.
When I shop for a model I always check their site. If nothing else they have some great stuff to look at. Wish my local shop had some of them.
Happy building and flying.