You shouldn't use objc exceptions for flow control, among many reasons they're a tad slow.

gistfile1.m

// Output on this particular Mac
//
// Exceptions took 5.054922
// BOOL return + NSError took 0.251062
// 

#import <Foundation/Foundation.h>
#import <mach/mach_time.h>

static inline void TimeDuration(NSString *description, NSUInteger runs, dispatch_block_t block)
{
    mach_timebase_info_data_t info;
    if (mach_timebase_info(&info) != KERN_SUCCESS) {
        exit(1);
    }

    uint64_t start = mach_absolute_time ();

    for (NSUInteger i = 0; i < runs; i++) {
        block();
    }

    uint64_t elapsed = mach_absolute_time () - start;
    double duration = (double)(elapsed * info.numer / info.denom) / NSEC_PER_SEC;
    NSLog(@"%@ time: %f", description, duration);
}


@interface Failer : NSObject
- (void)failUsingException;
- (BOOL)failUsingError:(NSError **)error;
@end
@implementation Failer

- (void)failUsingException {
    @throw [NSException exceptionWithName:@"fail" reason:@"total fail" userInfo:nil];
}


- (BOOL)failUsingError:(NSError *__autoreleasing *)error {
    *error = [NSError errorWithDomain:@"com.fail.total" code:0 userInfo:nil];
    return NO;
}


@end


int main(int argc, const char * argv[])
{
    @autoreleasepool {
        const NSUInteger runs = 1000000;
        Failer *obj = [[Failer alloc] init];
        TimeDuration(@"Exceptions", runs, ^{
            @try {
                [obj failUsingException];
            }
            @catch (NSException *exception) {
                // ...
            }
        });


        TimeDuration(@"BOOL return + NSError", runs, ^{
            NSError *error;
            if (![obj failUsingError:&error]) {
                // ...
            }
        });

    }
    return 0;
}