The cast Tarmac is a heavy rally wheel. 27lbs IIRC. As well, it is a gravity cast wheel, which is the equivalent of pouring molten alloy into a mold and letting it dry. This is the cheapest form of wheel manufacturing there is and also makes for the weakest castings as there is nothing but gravity to work out voids (empty spaces) and nothing to tighten up the grain structure.
The casting method used by Team Dynamics is called low pressure casting. In effect, the alloy is poured into the casting under pressure, which minimizes voids and increases grain alignment. Team Dynamics also heat treats the casting, which further assists in eliminating voids and aligning grain structure. This is basically a much stronger wheel when compared to gravity casting. Team Dynamics also shot peens every wheel. This process results in a tight grain formation, forged like layer on the surface of the wheel to prevent micro fractures.
I do not address appearance as it is subjective. IMO the Tarmac is a trendy, heavy, and pricey wheel. It is made somewhere in the far east at low cost. The Team Dynamics Pro Race wheels are tried and true european motorsport designs, manufactured in the UK by a world wide renown wheel manufacturer heavily invested in motorsports. As I have said many times, Team Dynamics Pro Race wheels offer the best bang for the buck in the wheel industry.
Adding a small bit of information. Gravity cast wheels are typically heavier as a necessity for strength. The premium alloy, low pressure cast, heat treated and shot peened manufacturing process used by Team Dynamics allows for a stronger, lighter weight wheel.