If you've ever worked in a startup, in tech, or in a corporation that went through acquisition/merger, and you're comfortable with BDSM, this may be the M/M romance series for you.
Takeover begins in a hotel bar where Michael, an out gay software engineer, picks up Sam, a closeted gay management consultant. The first 13 percent of the book is just their meeting and having sex - but Zabo's writing here is AMAZING. Sam's entire emotional world is laid out for the reader during this encounter. I have rarely seen a sex scene so effectively used to reveal a character's story and personality. Unfortunately for our heroes, they both turn up at work to find that Sam's new interim CEO position is at Michael's soon-to-be-acquired company. Despite both their shock, they forge a working friendship... which is undercut by their mutually anguished desire to connect, Michael's buttons getting pushed by Sam being closeted, and nasty corporate politics. (Do they end up sleeping together despite knowing it's not "proper or ethical"? Yes. Do they take the consequences gracefully? Yes.) I loved the growing respect in their working relationship, that they both find the courage to save their personal relationship, and that they're both such smarty smart-pants.
Just Business is the story of Eli, Sam's CFO at his new Pittsburgh-based consulting company, and Justin, the assistant they hire. Eli is a dom, Justin is a sub, they both have tons of emotional baggage (cw: grief, domestic abuse) - and Justin, at least, hasn't dealt with his at all. It didn't completely work for me - and I think there are significant problems with the disability rep - but there are achingly lovely parts, and Eli is a significant character in the next book who I wouldn't have appreciated as much if I hadn't read his story. (Diversity note: Eli is a Sephardic Jew and disabled from a car accident.)
Due Diligence gave me the two programmers second chance romance I've apparently always wanted. Fazil (bi), one of Sam's technical staff, goes with Eli to fix a company in Seattle. His high-school lover, Todd (gay), is (surprise!) working there as a programmer. Todd wants to reconnect, but first they have to deal with a TON of misconceptions and misunderstandings that broke them up in the first place. Most of that turns out to be Fazil's fault, and he has to work through his guilt while updating his view of his past relationship with Todd. I love how just because these two guys are older and have straightened out what happened, their issues don't just magically disappear. Fazil is still insecure, Todd is once again willing to just make a plan for their lives together, and somehow neither one of these very bright men consider (until way late in the game) Todd moving to Fazil's city instead of the other way around, even though Fazil's the one with the job he loves and Todd's company has -CONTENT WARNING- an extreme problem with homophobia and racism! But eventually Todd gets a clue and asks for help so they can straighten it out. Yay happy endings. (Diversity note: Fazil's family immigrated to the U.S. from Turkey.)
What I super-adore about all three books is the presence of gentle, understanding supervisors and mentors. Sam and Michael are given consequences for their inappropriate relationship by folks in the acquiring company, but they are appropriate, not punitive. Sam extends that same type of grace and humanity to Eli and Justin in the second book, and Sam and Eli do the same for Fazil in the third book.