Since acquiring the company, the Burgetts have brought back most of the piano models from the company's Boston era (1881–1932) that originally made the company famous. Some have been refinements of original designs, others have been completely new. First came the 5' 8" model A and 7' model BB, both of which had been manufactured by the previous owner and so needed less work to resurrect. Then, in fairly rapid succession, came the 6' 4" model AA, the 9' 4" model CC concert grand, and the 5' 4" model B. The development of the model AA was an especially interesting project: in the process, the engineering staff standardized certain features, refined manufacturing processes, and modernized jigs and machinery, improvements that afterward were applied to the company's other models. The 50" model 50 vertical piano has also been reintroduced and redesigned, with longer keys for a more grand-like touch, and improved pedal leverage. Internal parts for the verticals are made in Haverhill, then installed in an imported cabinet in the company's Sacramento factory, where it also installs PianoDisc systems.

All Mason & Hamlin grands have certain features in common, including a wide-tail design; a full-perimeter plate; an extremely thick and heavy maple rim; a solid spruce soundboard; a five-ply, quartersawn maple pinblock; and the patented Tension Resonator crown retention system. The Tension Resonator (illustrated in The Piano Book), invented by Richard Gertz in 1900, consists of a series of turnbuckles that connect various parts of the inner rim. In theory, this web of turnbuckles, nicknamed "the spider," locks the rim in place so that it cannot expand with stress and age, thereby preserving the soundboard crown (curvature). (The soundboard is glued to the inner rim and would collapse if the rim expanded.) While there is no modern-day experimental evidence to confirm or deny this theory, many technicians nevertheless believe in its validity because, unlike most older pianos, the soundboards of old Mason & Hamlins almost always have plenty of crown.

In the early part of the 20th century, Wessell, Nickel & Gross was a major supplier of actions to American piano manufacturers, including Mason & Hamlin. Over the years, the name fell into disuse. In 2004 Mason & Hamlin revived the name by registering the trademark, which now refers to the design and specifications of Mason & Hamlin actions. In addition to wood action parts, the company also manufactures a new line of nylon-based composite action parts of strikingly innovative design, which the company makes available to its dealers and to rebuilders as a high-performance upgrade to the traditional wood action. The company explained that it is gradually moving in the direction of using composite parts because of the inherent shortcomings of wood: it's prone to breakage under constant pounding, the parts vary in strength and mass from one piece of wood to the next, and wood shrinks and swells with changing temperature and humidity. Composite parts, on the other hand, are more than ten times as strong as wood; are built to microscopic tolerances, so they are virtually identical; and are impervious to weather. According to the company, material scientists predict that in the benign environment of a piano, the minimum life expectancy of composite parts is 100 years. In 2010, the composite action will be standard on all Mason & Hamlin pianos.

Mason & Hamlin grands are available in ebony and several standard and exotic wood finishes, in both satin and high polish. Satin finishes are lacquer, the high-polish finishes are polyester. Most sizes are also available in a stylized case design called Monticello, which has fluted, conical legs, similar to Hepplewhite style, with matching lyre and bench. In 2009 Mason & Hamlin introduced the Chrome art-case design, in polished ebony with chrome and stainless-steel case hardware replacing the traditional brass hardware. This design also has art-deco case styling, a silver plate, and a new fallboard logo in a modern font. This modern-font logo, along with a new slow-close fallboard, will become standard on all new Mason & Hamlin grands in 2010.

The tone of Mason & Hamlin pianos is typically American — lush, singing, and powerful, not unlike the Steinway in basic character, but with an even more powerful bass and a clearer treble. The designers have done a good job of making a recognizable Mason & Hamlin sound that is consistent throughout the model line. The 5' 8" model A has a particularly powerful bass for a piano of its size. The treble, notably weak in prior versions, has been beefed up, but the bass is still the showpiece of the piano. The new 5' 4" model B also has a large-sounding bass for its size. The "growling" power of the Mason & Hamlin bass is most apparent in the 7' model BB. The 6' 4" model AA is a little better balanced between bass and treble, one reason why it is a favorite of mine.