Number of Suits
The more suits the more challenging it will be to solve a game of spider solitaire.
No matter how many suits, you are playing with 104 cards. In the easiest One Suit version, all cards will be spades ♠️. In the Two Suits version, spades and hearts. Finally, the Four Suits version uses all four suits.
If you are a beginner, start with One Suit. When you get a hang of it, progress to Two Suits. And if you want to have a real challenge - try Four Suits.
Especially with the Four Suits version, make use of the undo-feature to greatly improve your chances to finish a game.