Hello again, looking at their web page it is apparent that they are an industrial specialty manufacturer. Very few engineers will know all of these specialty manufacturers and those that do will have limited experience with just one or two jobs as a rule.
A company does not survive however in that market unless they are competent, and honest... that market segment tends to attract high quality people.
The bad companies in this business tend to be in the residential market selling light weight, inexpensively built equipment...
Heatrex products are industrial quality. The chances you be hurt by a company like that are slim.
However your engineering and specification to them need to be accurate in order for them to build the heating element or heat exchanger
you need... ideally you will run the heater well above its minimum flow rate to avoid edies and hot spots in the heating element. And you will need good controls to kill power to the heating element as it approaches 80% of its maximum operating range.
The materials selected for the heaters need to be compatible with the fluids being heated...and the reliability of the design needs to comport with the damages and costs related to the heating element failure. (all systems fail sooner or later).
If you can tell me a bit about what you are heating and to what temperatures and which flow rate and how much the flow rate varies from minimum to maximum flow rate I can give you a better feel.
These custom build companies can easily be 2 to 3 times more expensive than a standard off the shelf heating element... if you can use an off the shelf heater you will save money.
Let me know more about your need, fluids being heated, and budget constraints. We can go from there. I will keep working with you until you get the answers you need. As long as you rate my ongong remarks positively I will hold the question open.