The features of Dylan's object system don't map directly onto the features found in C++. Dylan handles access control using modules, not private declarations within individual objects. Standard Dylan has no destructors, but instead relies upon the garbage collector to recover memory and on exception handling blocks to recover other resources. Dylan objects don't even have real member functions.
Despite these oddities, Dylan's object system is at least as powerful as that of C++. Multiple inheritance works smoothly, constructors are rarely needed and there's no such thing as object slicing. Alternate constructs replace the missing C++ features. Quick and dirty classes can be turned into clean classes with little editing of existing code.
Before starting, temporarily set aside any low-level expertise in C++ or Object Pascal. Dylan differs enough that such knowledge can actually interfere with the initial learning process.