Evap Coil transition question

I've got 2 bids to replace my current duct board transition which is falling apart. One contractor's bid is for a sheet metal transition (that I think is being custom made) and the other contractor's bid is for another duct board transition. The cost difference is minimal. Ever since I moved into this house, there have been problems with the duct board transition. It constantly leaks and is being retaped on a yearly basis (that is the reason it is finally being replaced). The "duct board" contractor says that his installation crew builds the best duct board transitions around. He claims you can sit on them and they use a more flexible, longer lasting material than hard cast on the joints. They are warrantied to not leak air for 1 year. He also claims duct board is easier to work with when servicing the evap coil and that he also has experienced the insulation coming loose from the inside of sheet metal transitions and causing the evap coil to freeze up.
Anybody out there have an opinion on this subject? What is the preference in a retrofit situation? Thanks in advance for your responses.
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Sheetmetal. No substitute. If you're concerned about pinned and glued ductliner insulation coming loose, have it wrapped and stapled instead.
- Robert
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Sheetmetal,and nothing else. Ductboard is absolute shit...period.
I have an installation that we are working on now, that the entire system was made of ductboard. I offered to replace it, and price was not an option, but the transitions here,will be of metal...period.
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