I use P&C alot, mostly because I live in an area with basically no brick and mortar pipe shops.
We have a crappy local smoke shop that mostly sells cigarettes, some mid-tier cigars, weed pipes disguised as tobacco pipes with a couple cheap tobacco pipes thrown in for effect, and like 5 OTC blends. Otherwise there's a couple chain shops with even less to choose from.
P&C is far from perfect, but generally they're pretty marketed toward less-experienced smokers with more budget constraints (at least in my experience as one of those smokers) and they fill that niche pretty well.
As for the bad...
Their tracking system is hopeless, their packaging often shoddy, and as mentioned by SobrBiker above they innundate you with random sponsored coupons for worthless junk in every package you get from them. Also their rewards/rebate program is kinda weird to navigate so I didn't keep that after my trial expired.
However, they sometimes have pretty decent sales and I've never had anything arrive wrong or broken personally in the year and a half or so I've been shopping with them. And their customer service was good the one time I actually had to call them, so I guess that's the best answer I can give.