The best part about Stampli was that I could see exactly where my invoices were going through their process so there wasn't any confusion as far as what stage they're at because everything happened automatically! There really isn't anything bad I can say about this software; however if you want something that will save time then go ahead and make sure Stampili fits into how things run around here (or whatever business you have).
It saved me hours upon weeks by making all our payments automatic which allowed us more free up time/resources once we knew when bills would be paid each month vs having them come out monthly throughout the year.