While I have no direct experience with these systems as a pilot, I have spent some time around them and may be able to answer a few of your questions.
Most systems do use electrical heater mats in the blades with mast mounted slip rings to transmit the power from the fixed to rotating system. The systems I am familiar do not use an anti-ice approach (like an engine inlet) which would require keeping the majority of blade warm all the time and would need an enormous amount of electrical power. A de-ice approach is commonly used where a limited of ice is allowed to build up on the blade leading edge and then a heater mat is energized, heat "melts" the bond of the ice to blade allowing the ice to "shed" due to Cf. The blades may be heated in zones and/or pairs to minimize vibration changes, torque rise and electrical power requirements. The frequency and duration of the heating cycles are adjusted by system based on the liquid water content (LWC) and temperature the aircraft is operating in (determined by ice rate sensors). Too much heat for too long could allow the melted ice to run back and refreeze on an unheated area of the blade or high temperatures could damage composite blades. Failure modes and impact (pun indented) of shed ice must be considered for certification.
As the brochure says "these are highly reliable, modern digital systems with built in redundancy, fail-safety and include manual mode backup to the fully automatic mode, self test and diagnosis capability." The operational reality, of course, is that controlling and moving significant amounts of electrical power through flexible wiring to heater mats in highly loaded whirling, flapping, flexing main & tail rotor blades while in a wet environment might provide the occasional engineering/reliability challenge. Or as the program manager says "we are constantly working to improve our highly reliable products".
Scheduled maintenance is relatively limited with brush block inspection / replacement, slip ring inspections, and perhaps bearing life replacement, wiring harness and blade heater mat checks. YMMV with unscheduled maintenance - a "simple" heater mat element failure could require blade removal/replacement & overhaul.
Aircraft performance can/will be effected by the de-ice system due to the decreased average aerodynamic efficiency of the blades as ice builds and then sheds (and other factors including the need to consider the built up of ice on the airframe). Any performance changes or other limitations will be defined in the RFM.
These system require significant electrical power, some operate on the #1 and/or #2 AC Primary Bus. Some aircraft are fitted with an additional generator for the de-ice system.