[rameumptom]

Yes, the Telestial Kingdom surpasses our understanding in how glorious it is.

That said, the caveat is mentioned in D&C 76. These are those who will be cast down to hell first. They will the ones who will suffer in Spirit Prison, even as Christ suffered (D&C 19), because they will not repent of their own accord.

Moroni told us that they would be happier with the damned souls in hell, than standing in the presence of God (Mormon 9:3-4), and Alma stated they would wish the rocks would cover them up and hide them from God's presence (Alma 11-12).

Their suffering will be similar to Alma's, as he suffered for 3 days and 3 nights in "exquisite" pain, until he finally was compelled to fully repent. It has been suggested that some are so sinful and stubborn that it could take them a thousand years to come around to fully embracing Christ's atonement and being released from Spirit Prison/Hell. Only then do they become candidates for a kingdom of glory.