In many cases, you should never have any problems with the battery. Good news is the battery should last a long time. If you're battery dies before your warranty is up, send it in the have the battery replaced for free. Note that most but not all warranties cover free battery replacement and free shipping. Some may require you to pay for shipping one or round trip.
Bad news is that it may outlast your warranty, unless you've extended it to 2 to 3+ years by PalmOne or another vendor. If something like this happens, you have several options, send it back to Palm, but pay for shipping and $125 'repair fee'. You could also send it to a 3rd party group to do the same thing. Else, you could go to places like www.pdaparts.com to purchase a spare battery. They'll have instructions (screenshots, and in unusual cases, perhaps video clips too) and maybe even provide the any required extra tools to swap the battery yourself. The idea is that at this point, your warranty is up so even if this will void your warranty, nothing ventured, nothing gained
Sure, if you're the unusual case where your battery goes out in mission critical cases, on vacation... then that certainly sucks and I would feel for any1 in this case. But frankly, I'd like to think that other issues may be at fault too. Bad screen, faulty circuitry, ..... stuff that PPC users will also go through.
As far as the validity of this concern goes, you're BOTH right. If the lack of user replaceable battery were such a big concern, Palm would've been down to MUCH lower than roughly half and half with PPC as far as the marketshare is concerned. Plenty of ppl are still using Palm devices. Some are quite happy, others aren't quite so but stay with Palm (or away from PPC in retrospect) for their own reasons.
Just think, ALL types of ipods don't have user replaceable batteries, but Apple is still selling them in droves. And they ain't ''invulnerable'' in this same regard either. You may have heard of ''ipod's dirty secret''. Their litium ion batteries will also near their life cycles end after the standard warranty, initially forcing users to shell out hundreds of $$ for replacement ipods. Ipod now offers $100 to send in your ipod to have the battery replaced. Not much better than Palm in the sense that you're paying 40% of the purchase price to have the battery replaced. You could alternatively pay $50 and do the labor part of it yourself.
Lack of user replaceable battery (URB) can't be ignored either. Quite a few folks have switched to PPC from Palm for the replaceable batteries. Again, some very willingly happily, others bitter about it and wishing Palm had done this too but find this feature too important to pass up. This leads to the cons of no URB. On the road by car, you'll need to purchase a car charger. By train or plane, if you're lucky, u'll have access to an outlet. Else, you'll have to purchase portable, on the road travel charger that CAN charge away from power outlets.
Depending on your occupation and lifestyle, if you can access your cradle/power cable at least once a day (office, school, home, whatever), then you should be fine as far as power management goes for most Palm models under moderate to moderately-heavy usage. If you use a Tungsten T3, this handheld's higher specs eats up battery quicker, so you'll need to recharge more often compared to other handhels. If this heavy usage also includes bluetooth, and/or especially wifi, you may have to charge more than once a day as you may end up using 100% to 175% of your full charge per day.
Ipods are exceptions to this of course. An 8 to 20 hour battery life would be insufficient to only the most hard core music listeners. (PDAs in comparison can last anywhere from 3.5 to 8 hours)
And yeah, i wouldn't hold your breathe on Palm coming out with a new model with URB. Palm likes to do it b/c it saves them $$. Unfortunately, as a small company, they need all the $$ they could get.
As far as this affecting your decision, it should be a larger concern only if you travel alot or away from power sources AND will use your PDA alot (wich doesn't affect most of us). Else, really look into Palm OS and PPC.... their hardware, OS, software to make a decision