Your plumber is not as suspect as some of the "advice" you are getting here.
First, you know the $49.00 flush is a loss-leader, meaning the contractor loses money on every job he "sells". There are many reasons for loss leaders, used by retail stores everywhere, the first being, it is promoted by advertisers. This practice is highly encourage by advertisers as it creates leads, or "hits" for their clients justifying the cost of advertising.
The second reason contractor might give things away (it costs any service provider $50.00 just to back in the driveway), is to meet and greet new customers.
Unless the contractor intentially condemns a current, functional, piece of equipment (a rare but not-under-heard-of crime) you always have a choice. Large plumbing and heating chains train commissioned technicians to "sell" up, but you have the final word and you can get a second opinion, any time.
All manufacturers of tank type-water heaters recommend annual flushing. Whether it is a good idea depends more on the water quality in your area, than age or operating time.
Most people are unaware of the preventitive maintenance required on plumbing and heating systems and wait-until-it-breaks to call a provider. This common practice can create health hazards, reliability issues and shorten the life of plumbing and HVAC appliances.
It appears that the plumber you met, and got to interview for less than the cost of dinner and movie, gave you good advise and likely installed the Watts LF 25AUB Z3 at the meter potentially saving you thousands in repairs on faucets and water valves on dishwasher, wash machine and ice maker all designed to operate below the 80 psi maximum dictated by the International Plumbing Code 604.3, which requires an ASSE approved pressure reducing valve.
As for the cost of the water heater, if a tank type water heater is 10 years old it has reached its expect life. Suggesting that it be replaced is likely good advice and the price he gave you was in fact very competitive for most markets. It sounds like he wanted to be your plumber.
The new energy code dictates a rather dramatic increase in residential water heater efficient (an unfunded mandate dictated by the federal government with zero input for you local plumber) the bulk of which will be achieved by increasing insulation. Heat pump water heaters are approved but are certainly not mandated by any model plumbing code I am aware of. Whether they make sense for you depends on the DHW loads/use, the comparitive cost of energy and your climate.
In predominantly cold/damp climates where the water heater may be in a basement the heat and moisture extracted from the space is a good thing saving electricity and recovering energy by using the waste heat in a cool, damp basement.
In Georgia the heat pump may work against you unless placed in a garage.
Source: www.BadgerBoilerService.com