Tedd, your taste in boats is similar to mine (I too had the TES and Seaward on my short list). I have not had the opportunity to sail the TES so cannot comment directly on its sailing characteristics. I have however sailed on the Solina 27 which has a similar ballast and keel design. The Salina 27 is fast, stable and settles into its groove quickly. The keel raising system is inside the keel trunk, consisting of blocks and lines which lead back to the cockpit for easy adjustments. These boats are designed and built in Poland which has a reputation for building quality boats at a reasonable price. The TES 28 is very popular in the Masurian Lake District of Poland. This region has over 2,000 lakes linked by rivers and canals and require frequent mast drops to navigate under bridges. That is why TES has come up with the ingenious integrated mast raising system. I have also seen these boats marketed and sailed in the Mediterranean and Baltic Seas for coastal cruising. You can find many videos on YouTube if search for Masurian Sailing and the TES 28 will be common sight.
I was impressed with the quality and spacious interior of the TES as well as the hardware above the decks. The hardware is frankly at par with the Seaward 26 which I have also inspected but not sailed. The Interior of the TES is, by far, more spacious and better designed than the Seaward and has more wood trim. The TES 28 is available with either an inboard or outboard options (the outboard option provides for more interior space).
As with any boat, there are compromises with pros and cons. If I had to pick one, it would be the TES mainly for its spacious interior and modern looks. The Seaward is a proven performer and more common which has its benefits.
Hopes this helps a bit and I look forward to finding out which one you have chosen.
Cheers.