I've been starting to buy from the herb shop in Lumiose city, because the price per HP is much better there. However the description of the "Energy Root" notes that it is very bitter, does this have any negative effects on my Pokemon, or does it not matter?
Does using “Energy Root” to restore HP have any negative effects on Pokemon
pokemon-x-y
Related Solutions
StreetPass provides you with an amount of PokéMiles (PM) for each person you've met who is also playing a StreetPass enabled X or Y. PokéMiles can be traded in for items at the Lumiose City Pokémon Center. Alternatively, you can redeem them at the Pokémon Global Link website via the Game Sync feature of the PSS; the prices there are lower than in Lumiose, and the items you select will be delivered to the Pokémon Center of your choice. Eventually, you will be able to use your PokéMiles to play mini-games called "Attractions" on the Global Link website and win items, though at the time of this writing, no Attractions have been released yet.
To get rid of that green StreetPass light on your 3DS' homescreen, you have to go to the PSS (on the touch screen) and open up the Holo Caster (not to be confused with the Holo Caster item in your Bag). Once you're there, hit "check announcements." Then hit "Streetpass News" and you'll be notified of how many people you've StreetPassed, how many PokéMiles (PM) you got for that, and your total PokéMiles.
You can also earn PokéMiles by trading or battling with other players online (this includes Wonder Trade and GTS trades). The number of PokéMiles earned (either via StreetPass or online interactions) is based on the distance between the locations set on both players' systems; international interactions are worth more than local ones.
There is a website/webapp that provides a Pokedex style Checklist.
Each Pokemon has a check-box next to it which you can tick to mark if you currently have it or not.
If it evolves, you can simply untick it if you don't have a duplicate.
I'm not sure how the site stores the information so I assume it's locally which means the moment you clear your cache/history etc, you may lose your checklist and unfortunately it's not up-to-date with X and Y Pokemon yet.
The website can be found here. I don't think there is an iOS or Android app though. Good luck.
Best Answer
Herbs are indeed generally cheaper and you also have access to the Revival Herb which is an equivalent for the Max Revive, which you might find more worthy than a simple Revive (which recovers only half of the max HP of a fainted Pokemon), but there is indeed a side effect. These herbs affect the happiness of Pokemon.
According to the last generations, herbs reduce the happiness of Pokemon by a certain amount (contrary to fainting which decreases the happiness points by 1 each time):
Table sourced from bulbapedia and assumed to be similar in Pokemon XY.
What happiness points mean in-game are:
Some Pokemon evolve when their happiness points reach a certain minimum of 220 happiness points. You can see a simple table containing such Pokemon here.
Return and Frustration are moves that are affected by happiness. Return's base power increases with higher happiness whilst Frustration's power increases with lower happiness. Both have a maximum of 102 base power.
From the last point, some might even argue that reducing happiness has some advantages. It's just that it's more difficult to decrease the happiness points of a Pokemon than to increase it.
Lastly, happiness does not have any relationship with affection.