I'm sorry, and with all due respect, but that's an unnessasary comment. What would you rather have? Being put on the next BA flight a couple hours later or go on/close to scheduele but on a different plane?
The bottom line is that BA made a big effort, also financially, in getting you to London asap. They could have just taken the easy option and re-booked you and left it at that. But purely the fact that they wet-leased an aircraft to get you all home shows commitment to their operation/promise.
Yes it's not a shiney new Embraer but the bottom line is that you get from A to B on scheduele. Over the past weeks I've seen numerous Swiss cancellations due to tech aircraft. That rarely happened but it seems more common nowadays. So to be honest, I wouldn't put my money on Swiss nowadays.
I hope you still re-consider flying BA next time and can also see the effort being made by BA to get you home.
P.S. I believe the reason behind subcontracting Titan was that some crewmembers (incl stanby crew) went sick.