When comparing IPOCC and ACCS it all depends on customer needs both products can do a lot when done properly.
Now if IPOCC goes away the question is what product you wanna sell to your customers.
Learning ACCS requires a lot of work, but the same should have been required for IPOCC.
IPOCCs biggest problem was that it was given to resellers without the proper training, it's easy to setup but there are many things that can go wrong if you don't understand the inner workings of the product.
I works as a consultant with IPOCC (among others) so I've seen many installations where the issues are actually caused by how it was configured.
That's more Avayas fault than the techs since docs and training where made simple so you could jump on the product quickly.
"Trying is the first step to failure..." - Homer