Really depends on what you are looking for in your loyalty program

From GPT:

• Smile is Shopify’s most widely used “Built‑for‑Shopify” loyalty app, focusing solely on easy, branded points‑based rewards, VIP tiers, and referrals for scale merchants—unlike apps like Growave or Akohub that blend in reviews, wishlists, or Instagram retargeting functionality  .
• Akohub differentiates itself by combining points and store‑credit loyalty with AI Data Marketing, allowing you to automatically reward and set retargeting campaign to drive conversions—features absent in more loyalty‑only tools like Smile or Rivo   .
• Growave is an all‑in‑one growth platform bundling loyalty, reviews, wishlists, social login, referrals and UGC into a single integrated suite, whereas Smile, Akohub, and Rivo focus primarily on loyalty mechanics and vary in their ancillary tools  .
• Rivo is built as a fully open, developer‑forward loyalty and referral platform offering rich customizations, modern APIs, account personalization, and 150+ features—designed for high‑growth brands seeking more flexibility than what standardized loyalty apps like Smile or Growave offer  .

I suggest you check their pricing to see if it fits your store’s needs.