Catalogue & checkout
JTL-Shop
The evidence gives me 'unlimited articles' and 'Integrationen zu allen beliebigen Payment-Anbietern', and that is the entire catalogue-and-checkout story — not one word on variants, bundles, tiered pricing, guest checkout, promotions or vouchers. Payment integrations exist, so it is above the flat-list floor, but silence on everything else caps it well below the standard-checkout anchor.
Shopware
The variant model is the real thing — self-referencing parent-child products with a configurator that assembles property groups and variants, hierarchical categories, unlimited property groups for filtering, and products addressable across multiple sales channels. Payment breadth is thin in the captures: PayPal is the only provider named, and I found no public information on bundles, promotions and vouchers with rules, guest checkout, or invoice and direct debit as payment methods. The checkout itself is documented as customisable without a rebuild via the Store API, payment handlers and the state machine, which is what lifts it above the standard tier.