I have been in this exact place before. For the two of them, this day will be just about the worst of their lives.
This is ordinarily when hard-core criminals are taken into custody. If their experience was like mine, they had to show up in front of a magistrate with their lawyers, plead not guilty, then go to a dungeon for about 30 minutes while they get handcuffed, fingerprinted, mugshotted, and DNA-swabbed. Then, off they go until trial. It's basically like being free, but you have to stay out of trouble and report all contacts with law enforcement.
Being rich (or from money), they won't have to worry about federal defenders or CJA representation, which wouldn't be near as bad as dealing with a state-funded public defender. There's a small chance they'll have to go this route anyway, since the government can snatch the money in dispute and block you from spending your ill-gotten gains on high-priced legal representation.
Don't let the "sticker price" fool you. They're not going to have to serve consecutive 20-year terms for what they're accused of, even if they take it to trial and get found guilty.
They will probably get their first plea offers in about a year. Most people take the plea. In the event they refuse to plead guilty, trial will probably take about 2-3 years from today.
Holmes will be offered, I'm guessing, about 6-9 months and a joint-and-several "money judgment" (restitution + forfeiture). Balwani, about 5 years and a joint-and-several "money judgment". This may be a package deal too, so Holmes may not be able to take it if Balwani won't. Why the discrepancy? The 28th amendment hasn't been ratified yet.
Before my experience with this world, I would have been eager to join in the collective bloodlust, with the pitchfork-and-torch crowd clamoring for these overprivileged defendants to sit through a trial and rot in prison. Take it from me: I wouldn't put my worst enemy through even just the trial.