How do you feel about a Guaranteed Category booking as opposted to a definite cabin assignment?

I have done it but probably won't going forward. It depends on a person's needs. If being nearer the elevator is important, it is best to book a specific room.  At this point in our lives, being near the elevator is an issue.  If it really doesn't matter, then it is one way to save a few bucks.

I always want to know which cabin I have and where it is. Keep in mind we always book handicap cabins, but I still want to know where it is located.   Never, never let someone else book your cabin.

BAK1061,
We try to get accessible cabins but often those are booked so far in advance that the best we hope for is something closer to the elevator.  That said, in 2016 we have B2B2B on Princess and got a mini-suite but could not get an accessible one.  Come 2017, we booked a Sky Suite on Celebrity Eclipse and got the same accessible stateroom for all four legs of our time on board... but to do that, we had to book 2 yrs. ahead.

Oh I know. We usually book at least a year in advance. I've even been able to book the same cabin a year apart.

It also helps if you've been on the same line several times. Norwegian always seems to find one for us. Our August cruise was booked in November. I asked for, but couldn't gt the cabin we had last time, but she found a better one on the same deck as the spa.

When I started cruising I was 20 some years younger I would always book run of the ship,  category guarantee.  The advantage of it is that I got a lot of upgrades that way.  I had got from inside to ocean view and from small balcony to one of the extra large balcony cabins.   Back then I could sleep through anything and $ was tight.

Now I like to know where my cabin is so I can get in a quiet area. I still do a guarantee sometimes on a short 3 or 4 night cruise but for a 14 night cruise I want to pick my cabin. 

With Guarantee cabins we have still gotten 2 or 3 cabins next to each other when traveling in a group. 

I don"t know the details, but for our honeymoon cruise 32 years ago we didn't even know before a week or two out what ship we would be on. We ended up on the Norwegian Skyward in an inside cabin (I hated it). Now we choose our cabins. 

I know a couple who booked Guaranteed Category and landed a handicap cabin.  They hated it because everything was low down and they are tall people. 

When we were forced to book Guaranteed Category, we did it only because that was the only way that we could travel with our group of friends who were going on a particular cruise.  We were away when the trip was first announced.  But it worked out for us.  I just don't like the uncertainty. 

What a cruise line considers to be an upgrade may not seem the same to me.  For example, would rather stay on a lower deck mid-ship and be placed on a higher deck near the bow. 

If you get a room in the bow,  you get your port day wake up when they drop anchor and you hear every link of the chain clunk on the way down.   I forgot  about that and have the most forward cabin on the Glory.   I had not been near the bow in decades and forgot about that.   I got a reminder and will not do that again.  I did like more that I felt more of the ship moving in the bow.

We have always picked the cabin, in consultation with our agent.

Since our first cruise was a special occasion we had an Oceanview, Our Panama was an inside cabin but very close to the stern balcony on deck 8 of the Island Princess. Best room in the house. On NCL we had a great Inside on Deck 11 right behind the stairway and close to the elevator. I have heard that if you let the cruiseline pick your spot you may get an upgrade, However, those are really few and far between.

We booked guaranteed balcony for Panama Canal cruise last year my dad & step mom got a balcony room at the very back of the ship with balcony the same size as the room!! Huge!!! We got a standard balcony room. You just never know!!