Yes Sealine do make a pretty good boat. They manage to make very good use of space on all the boats they design.
Their reputation is good in the UK although their quality of workmanship back in their earlier days seemed to get a bit of a beating. In reality they are very good at what they are meant to do, and that is fun on the water. I personally prefer the lines and slightly more over engineer'd Sunseekers but you are also talking a big difference in price.
If you find one and the price is right I would certainly say buy one.