I find PLing extremely bad for anyone, and pretty distasteful to boot. So distasteful that I refuse to get one personally or be in a party that brings one in. I simply disband and go seek again. I actually rate it only slightly better than people that support that farce of a business in gil selling.
Unfortunatley, both of these problems exist, and lazy people will use these "services" with the shallow excuses of "I don't have the time to level" or "I don't ever get enough gil playing". I accept that they exist and won't go away, but refuse to support either of them as an acceptable use of the game. If you don't have the time to work on your own character, find a game that doesn't take up so much of your precious time.
Several good points have been raised by posts earlier in this thread, and I'll admit that a few of the people supporting Power Leveling have valid claims to use it. However, I'll support or deny these cases as they come up. There's more at stake than a few quick levels for an impatient player.
1) Skills suffer - Damn right they do. All the skills you use in the game only improve if you use them a lot. And don't pull the 'but I sat outside my Mog House and leveled my skill for 2 hours' routine. Whm's Holy magic skill won't get a tenth of a point from that, and Blm's are SOL unless they're casting on something that'll take damage. It's also pretty hard to do a skillchain when your 2 Wars only know Fast Blade and Hard Slash. Keep this one in mind too: Enhancing and Curing magic tend to get faster skillups when being cast on someone who actually needs it.
2) It's okay, I'm getting PowerLeveled past the problem levels -
No, you're encouraging people to not learn the dynamics of forming and supporting a party. I've very rarely seen a personal Power Level in progress, it's usually done by a hi-lev on top of a party that's already been formed. In fact, I've seen several people in the Dunes shouting at the top of their lungs for invites because they bring a powerleveler with them.
3) No harm, No foul - BS. As in the example directly above, the person bringing in the PLer may or may not be within shout range of the party that brings him aboard. The party leader may also just want a PL as well, and ignore the fact that any of the members of the party want to LEARN how to play their jobs instead of being spoonfed experience. Hell, FFXI is a global game, the party members may not speak English! {gasp} This is especially crucial at early levels, where limited ability, spells, hitpoints, and skills need to be worked with so that the players learn the limits and strengths of each of them. Not letting the tank die for using Berserk (Attack up, DEFENSE DOWN) because he just got a shiney new job ability means he'll keep doing it even further on in his career as that class. It also forces you to use Teamwork to set up chains of difficult enemies, not just Toughs, instead of dying for going {Full Attack!} all the time because the WAR gets it into his head that only IT++ mobs are worth killing.
This general lack of player experience and research reflects poorly on Americans as a whole, causing a bit of a split between us and the rest of the world. In fact, there are plenty of players who {do not speak any English} who can understand most of what's being said around them, and cringe when the party around them calls in a DRK or DRG to be main tank. Have any of you been to Yahoator Jungle during American off-hours? About 7-11AM EST? The Kazham zone is clear. I've never seen a JP party zone a Mandy or Gob because they bit off more than they could chew. They work out a procedure and get organized into a clean leveling unit that regularly gets chain #5's. Granted, in Japanese cluture teamwork is ingrained, but they all pretty much brought their characters up from scratch without any tricks.
Some of you may accuse me of giving/recieving a PL myself. Okay, you've got me. I've given a power level to a friend on a rare occasion. Let me reiterate: a friend. He or she had proven to me on several occasions that they were competent and knowlegable, had been through Yuhtunga and realized that having 3 mages and 1 'voker made dead parties. I also only popped them up level to get their next set of armor/weapons equipped. The most important fact is that I didn't get paid gil bought from IGN to do it.
Now recieving one, I've only technically done so with my second character, and that was mostly ******** around. It had started with just a pair of low levels kicking orcs around in Ft. Ghelshba, until my partner's fiancee showed up to chat and show off his summons. With that setup, I figured 'what the hell', knowing that if I could hit a higher level mob, I'd get better skillups. So, I went on {Full Suicide} and attacked anything that looked at me funny. Kudos to Tillis and Niekolaas for keeping up with a suicidal elvaan(YARR!!). Even though we ended up with only a level and a half from our run through the place, I got my Great Axe skill from single digits up to the low 40's in a short period of time.
As PLing does NOT break any rules in the TOS, or is mentioned in any way, the whole issue is one of opinion. Granted, this rant of mine's a bit lenghty, but what I've seen is that only huge posts on Alla get any kind of attention at all, and that you've all probably rated this post before you've even read down to this point.
Perhaps I shouldn't post when I'm tired and frustrated after proving that Mithra make better Tenshodo airship courriers with Tillis 3x over. Vents of your true opinion usually get shot down anyhow.