I'm confused. First of all, I don't have a buff bot, let's get that out there first. Second, I fight a LOT of buffed assasins.
How to beat assasins:
1) If you don't have all MP equipment, you're F'd. Don't complain that "oooo, it takes time and money" No sh-t. Dump that crappy "look what I found on a raid" item and get some serious player crafted stuff.
2) Get it overcharged so that you have +200 hp, +75 con, +75 str (with spear), +75 dex/quick (with bow), +11 spear (with spear), +11 bow (with bow), +11 stealth, +26 body/slash/thrust resist.
3) Get the high level DoT procs put on EVERYTHING.
4) Spec spear to 44. Don't listen to numb-nuts who come on here and say 10 spear is fine.
5) Make sure you have beastcraft of 32 at least for instant pet.
Okay, once you have the equipment and spec's, you're probably going to be able to beat moderately buffed assasins. At this stage, you'll still lose to fully buffed assasins.
To beat fully-buffed assasins, you need IP, and to some extent purge if you get stunned.
Since Hunter's have poor defense, I don't really get overly worried about making it worse, i'm more interested in dealing out massive damage, since assasin don't have that many hit points and can't heal themselves. I assume that i'm going to get hit by an assasin, so "which style has less defensive penalty" really doesn't worry me.
As a result, I'm primarily an Engage-->Wounding Thrust player. I throw in Razors Edge when I get lucky. I ALWAYS use the pet in the fight.
As for tactics, this is where a lot of hunters get stupid. I have pretty high stealth (49 effective), but I still don't run down the main path. Not because i'm afraid I'll run into an assasin, it's because I'm afraid I'll run into 2 or more.
Use Truesight at milegates or other chokeholds. This is of course, a total pain. Assasins on my server (and we have a lot), either stand on the path from the portal fort or at the milegate. Since I don't run on the path, the only time I really need to think about assasins is at the milegate. If you see an assasin, send in the pet and restealth, and re-camo (muhahaha) and move in to shoot him when he starts fighting pet. Kite and repeat. Finish off with a good wack with your spear just to teach him a lesson.
Of course, the #1 reason assasins beat hunters is because they get the jump with a very impressive PA + CD combo. PA can be avoided much like a crit shot. I'm always amazed at how archers say crit shots can be easily avoided, and yet they continually get Perf'd themselves. How to avoid getting perf'd.
1) Don't stand still. I constantly shift in random directions when I'm in a stationary place. Lining up a perf is too hard, and assasins (thinking they can outank GOD himself) wont bother using the perf and will just hit you with a normal melee shot. At this point, you just beat the holy sh=t out of them and use the pet, and then proceed to laugh your butt off afterwards.
2) If for some unholy reason you must stand still, face a tree or some object that makes getting in front of you difficult or impossible. You'll be backstabbed, but that's easier to handle than perf.
3) If you are perf'd (it happens, as assasins learn to try it after you kill them repeatedly), straf and move to avoid the CD (the real killer). Thus, you took some heavy damage, but avoid the stun. If you are stunned, you're gonna need purge. If you avoid the stun, you can cast the pet and back off. This appears (to me anyway) to slow the assasin's attacks down, allowing your pet to munch more on the assasin. You still fight the assasin, but don't just stand toe-to-toe, back up and fight, which slows down the damage you take but increases the damage he takes due to the pet. On a non-buffed assasin, this is enough to win (I beat a rr3 infiltrator while res-sick using this technique, which I assume was unbuffed or so unskilled that he can't compete at pong
(huhu j'ai bien ri là )).
On a buffed assasin who gets perf off, you'll need IP. I beat a rr6 infiltrator who was buffed to hell and gone who also got off perf on me (sigh, opened the mg door and bam, good for him, hehe) with IP, but it was extremely close.
How often do I lose to rogues:
Solo, hmmm, not often (don't really remember last time actually). It usually is when I fight one assasin, and then am still recovering when 1 minute later another one jumps me. Sigh, gonna happen. Most assasins now pair up, which makes soloing as an archer even worse.
Words of wisdom.
Yeah, i've played this game a lot, earned a lot of realm points. I zerged, I solod, I 8v8, fort defense, fort offense, sniped in DF, done it all. I've faced every class and every player, good and bad. There are better hunters than me on Bors, I just happen to have more RPs (more RPs doesn't mean more skilled, although I do think I'm definately above average).
The archer class was designed to solo. Look at the abilities: Stealth, some small buffs, and a short-duration speed buff. Nothing to offer to a group. With See Hidden (and fewer folks running around solo), a solo archer is not that viable (or incurs massive amounts of boredom, if that's your cup of tea).
However, there is an overlooked ability that Hunters do bring to a group, and I think you should remind your groupmates of that ability, and you should try to maximize that skill. You can kill casters at range.
I always reminded my groups that I would faithfully target the caster that was the most dangerous in any group. This resulted in me always shooting the right people. Even if I didn't kill them, I was key in interupting them, saving my group. Bards and AOE casters were usually top on my list, then healers. Some groups after a while began to appreciate that committment and finding groups became easier, despite my lack of ability to bring something unique to the group.
Another tactic I use frequently (and very effective) is to run first in the group towards the enemy (yeah, charge first). Just as I see casters begin thier animation to cast, stealth. Hahahahaha.
This totally messes up casters and allows your tanks to get closer without getting nuked. Allow your group to pass you (while stealthed) while you figure out (fast) who is the most dangerous caster/bard.
Well, hope all that helped. I don't think that because I'm RR7 has that much to do with it, but I do acknowledge that IP+Purge+Truesight have been my best friends.