A bit of product unendorsement: if you must use a tour bus service to get around Guatemala and neighbouring countries, here's one to avoid: Tierra Maya on 6a Avenida Norte (next to El Viejo Cafe).
Notwithstanding that Guatemalan operators of such services appear all too aware of the way that shuttle rhymes with cattle, I have made occasional use of them, for airport dashes in particular.
When I left San Cristóbal I had the option of getting the OCC bus, but on my last night I had wandered past a travel agent and found that they offered a direct service to Antigua for 400 pesos which would, I thought, enable me to avoid the uncertainties of border bus changes and the difficulties involved in arriving after dark in the capital. (Though with hindsight, given that this journey was to take 12 hours in the end, I might just have well have returned via Tapachula on the ADO/Galgos route.)
I have few complaints about the service up to the border. The driver was friendly and professional, introducing himself and making short information announcements throughout our ride to La Mesilla. Unfortunately, the way these things work is that the company you have paid to take you to Antigua hands over to their Guatemalan equivalent at the frontier.
This involves a change of microbus (usually something of a downgrade) and in my case a bit of an argument about the re-location of my suitcase. It contained cosas delicadas and I was loath to leave it sunning itself up on the roof rack with all the mochilas, but even though there would still be plenty of space inside, I was still given a load of aggro over this.
The new driver — Eddy — drove us to Las Cruces and then dumped us beside the highway, having informed us that another vehicle would soon be along to collect the Antigua-bound passengers. After about half an hour he returned and admitted that the other shuttle had been detained by a blockage up ahead, and that we would all now have to go to Panajachel where another driver would take us to Antigua using the alternative route.
By now it was dark and our third driver was in a big hurry, preferring to press ahead predominantly in the lane designed for vehicles travelling in the other direction. A German girl behind me called out to him "Señoooor! queremos llegar a Antigua..." He gruffly replied that he too wanted to get to Antigua, but the previous bus had been delayed and now he was running very late. Our safety was clearly of no concern to him whatsoever.
He had earlier made note of the various destinations within Antigua of my fellow travellers, offering hotel accommodation where none seemed to have been arranged, but when we finally made it to our destination, he pulled up outside the Tierra Maya office and declared that we had arrived in the park. Servidos...
I've done this journey before and have previously had no trouble persuading the driver to leave me to last and then run me home. Now you might think that in this I have been spoiled, but I do think this particular so-and-so owed it to his other passengers to take them to their various hotels and other abodes in the centre of town...or at least the Parque where they could more easily have picked up a cab.
There was a middle-aged / middle-class Mexican couple on their first visit to Guatemala on board and Antigua must have seemed a dauntingly unfamiliar place in which to appear at 8:30pm — unlike SC de LC, taxis here tend to congregate in one place, so the pair faced a bit of walk, lugging all their cases.
There's a certain kind of business here in Antigua which appears to believe that gringos are so many objects to be moved around and that delays, fuck-ups, rudeness, suicidal driving etc. are nothing to be apologised for. Tierra Maya is obviously one of these.
At the Mexican end it's probably best to ask who they subcontract to before setting off.