@pleonasm - I would suggest if someone wants specific recommendations on what kind of equipment to buy, that they have a look on relevant forums and review sites.
Try to make sure the websites aren't biased towards a particular company.
I haven't ever had to buy a stud welder myself, but whenever I need to make a major purchase, this is the first thing I do. People will almost always have a rough consensus on what are the best brands, and why, and they will also be able to give you recommendations depending on what you are specifically hoping to accomplish.
Don't rely on that exclusively, but I find that getting a bunch of knowledgeable people together is often the best way to get a grip on what the real deal is.