I have an earlier seagul and it was my first move to medium format. I think it was a good move because it taught me to meter with a manual meter and it made me want to move to a more versitile system or a better TLR. They are not built well at all. the optics are okay but not great. FOr the same price as one of these new you can get an older yashicamat or Mamiya 330. They will be much more relaible and have better optics. For not much more money and some patience you can land a used rollie which will be even better. In this day of dumping older cameras for digital crap I have seen some things go cheap on ebay. I've used all four but only bought the the seagull because I wanted to save a little money in the beginning. I used the other three brands when I realized I wanted something better.
If you do not want a fixed lens camera and can afford it the older mamiya 645's are going pretty cheap these days. The glass is not over whelming either. the next step up would be the Bronicas and so on. I went the kiev route because I am insane stupid or both but the glass is great and dirt cheap.
Decide what you want. If you want to play and throw away money the seagull would be the way to go. If you want reliability and are set on a TLR spend the few dollars extra for the used Mamiya or Yashicamat or even a rollie. It will be worth it in the long run.
Once you see a bigger negative or chrome you will be hooked. Then you are on the slippery slope of addiction. Pretty soon you'll be on the street panhandling with a sign that says "I need a 12x20 please help". Trust me you are taking a dangerous step. I am up to 5x7 and am jonesing for more square inches on the negative.