I wouldn’t say bonding two DSL connections was disappointing at all for me. I like the fast upload that LTE provides, but I liked the consistency of the DSL lines.
For a 50-67% increase in upload/download, it seemed to work easily and well and consistently. It might be a high price to pay for the % increase, but I didn’t want to go back once I plugged in the two ethernet cables.
The reward of the upload speed of LTE seemed far more exciting – since the upload could be an order of magnitude more instead of a 50% increase – but more difficult.
I wanted to bond for a single use/user, not load balance.
I was also a long distance from cell tower (so a cellphone barely works at all), had a cell plan I feared could be deprioritized if I used too much data, and wanted to keep latency very consistent and low if possible.
(Not disagreeing with Martin’s post – he is the expert and helped me a lot. But I didn’t personally have any regrets bonding the DSL, so if what you can get is two DSL lines I’d still consider it.)