I traded my DPO for a second Mangrove a little while ago and haven't looked back. I thought I would miss clean(er) sine to sine FM, but I've just moved to doing it with my Sisters and a uVCF. Using the formant outs on the Mangroves and sending each module's square output to AIR on the other is something I've had a lot of fun with, and is something I never really got to explore with the DPO (on its own, anyway) because vactrols. I definitely agree with @Larrea about doubling up on the Mannequins stuff. I want to get another Cold Mac (one for audio, one for CV) and another Sisters (one low pass isn't enough) now.
Would love to hear some other patch stories for a Mannequins complex osc-sequel set up... maybe we should start a new thread.