All mods require maintenance, such as the cleaning of the contacts, springs, buttons, etc..
Rhodium plating allows you to go for longer intervals between cleanings, according to rumor.
Brass is a bi-weekly chore, to assure great hard working contacts.
Silver is a weekly chore, but hits the hardest out of all of the above, so well worth it.
The key word, is "you". You have to be willing and confidant to clean your contacts as needed or on a schedule before as needed.
The Poldiac and the Roller, both have video instructions at youtube on how to take them apart, clean, and put them back together again. Roller has a great FAQ support pages section at their site, Atmizoo.com and the Poldiac has a forum with lots of helpful people. You'll never be stuck without help from either one of them. They both have threads in many forums, with great posters
The Poldiac can be bought with either silver or brass contacts setups, or you can purchase the opposite one and have both. You can also take your contacts/spring to a jeweler and have them either silver or Rhodium plated.
The Roller also now offers the 3 choices (brass, silver or rhodium).
Would I recommend these to a newbie? Oh heck yes! If you're not ready today, hang on to it, study the threads/video's, and be ready tomorrow. They both hit hard, are lovely to hold, and are fun to dress up or down.