I have given up on TM because it chews up my external drives at an alarming rate. I have had three hard drives die in the last 2 years because of TM. My other drives of the same brand that didn't have TM are just fine still. Either I have extremely bad luck with WD drives, or time machine is just not a reliable backup mechanism (I'm inclined to think the latter). Plus, the drives have to be HFS formatted which is also a con for me (that I am willing to live with in exchange for a reliable backup solution).

Is anyone else experiencing these kinds of problems with TM?

I've had the same drive hooked up to time-machine now for the last year and a half if not longer and haven't had any issues what so ever.

It is a custom enclosure with a standard Seagate hard drive. Works wonderfully.

I've only been using Time Machine for about a year but my hard drive just crashed last week, conveniently three days after my MbP's hard drive. I've found it useful for restoring individual files, but I wish there was a way to customize the frequency of backups- plugging it in once a week is hardly ideal.

You can change the frequency, but you have to use an external app. There are a number of ones out there, for example: http://timesoftware.free.fr/timemachineeditor/ or http://www.klieme.com/TimeMachineScheduler.html

Note: I can't remember which one I tried so I can't recommend one, these are just quick ones I found off Google. I do remember as I used them that despite scheduling it in the App, time machine would incorrectly display "Next Backup: Tomorrow" or something like that.

I'm sorry, I have genuinely no idea what you're talking about.

Time machine is free. Apple isn't making money from that. You're thinking of Time Capsule, which is an external disk people often use with time machine.