The short answer
Yes, with the usual condition that applies to every breed: the right individual Appaloosa is an excellent beginner's horse, and there are more right individuals in this breed than in most. Appaloosas have spent generations working as ranch horses, trail horses and family horses, jobs that punish a flighty temperament and reward a calm, thinking one. A broke, middle-aged Appaloosa who has been ridden regularly by ordinary riders is about as forgiving a first horse as exists.
The temperament you are buying
The typical Appaloosa is level-headed without being dull. They tend to look at a new situation before reacting to it, they are sure-footed from their range heritage, and most are genuinely versatile, happy to do a schooling session on Tuesday, a long trail ride on Saturday and stand quietly to be groomed by a nervous new owner in between. Many are also smart in a way beginners find encouraging: they learn a rider's routine quickly and settle into it. The honest caveat is that the breed can produce stubborn individuals who test whether a rider means what they ask, which is a training question to settle with lessons rather than a reason to avoid the breed.
Why the individual still rules
Beginners get into trouble when they buy the breed name instead of the horse. A four-year-old Appaloosa with ninety days of training is a green horse wearing a beginner-friendly label, and green horses make their own decisions when frightened. What you want is mileage: a horse in his teens or late single digits who has been ridden by amateurs, hauled to shows or trailheads, and handled by different people without drama. His price will reflect that education, and it is the best money a beginner can spend, because what you are really buying is the previous owner's years of training.
Choosing and trying yours
Ride any candidate more than once and in more than one setting: in an arena, out around the property, past the things that make horses look twice. Watch him being caught, groomed, tacked up and loaded, and handle him yourself on the ground, because a beginner spends as much time leading and grooming as riding. Ask what he eats, what work he has been doing and why he is being sold, and arrange a pre-purchase veterinary examination so soundness questions get answered before he is yours.
Bringing him home
Once the sale is agreed, the paperwork matters more than most first-time buyers expect: vaccination and dental history, his current feed and amounts, his quirks in the stable and under saddle. Get it all in writing from the seller while you still can. KinsLe's Transferrable Profiles is built for exactly this handover, moving his profile, records and routines to you intact so your first months together start from his real history rather than guesswork.