By slicer you mean a beefsteak, right?
Link below lists many favorites - it is just one of many discussions about favorites that the search pulls up - but my personal favorites (not necessarily in order) are Giant Belgium, Black Krim, AR Traveler, Brandywine Suddith, Mortgage Lifter, Beefsteak, etc. just to name a few.
Here is a link that might be useful: favorite beefsteak discussion
Are you looking for just a sandwich-accompaniment type or for something that also looks good on a plate or in a salad? I think there's no more beautiful sight than a plate covered in rainbow slices, wth just a little drizzle of olive oil and some ribbons of basil. What I normally grow is Mortgage Lifter (pink), Big Rainbow (yellow/red), Big Zebra (green with red blotches), Black from Tula (purple), German Red Strawberry (red, of course!) & Yellow Oxheart. But the Big Rainbow, Big Zebra and Black from Tula we find to be too sweet for sandwiches, so we do just use them in salads or just eating out of hand when we want a snack. So of my list, if you are only looking for an all-purpose-type plant or 2 to grow, you can't beat Mortgage Lifter (Estler's, preferably!)
I am looking for a decent multi-purpose tomato that isn't too sweet to use on either a sandwich, salad, or plate. I also don't want anything too big.
My favorite fresh eating sliced on a plate by itself tomato is Julia child. Its a 4 inch beefsteak that has great flavor, then finishes with a tart and sweet burst. Close seconds for pink tomatoes and I mean that these are really very good, are brandywine pink and Suddeth's and Brandywine OTV. For a black tomato, I also really like black krim for its bold, complex, almost smokey flavor and I find it sweeter than the other blacks. I also like amana orange for its very sweet mild flavor. A good all purpose tomato that a lot of people like is cherokee purple because of its production in addition to taste. My favorite all purpose tomato that does pretty well for slicing and eating fresh is itallian heirlom. It's not quite as flavorful and tasty as the bradywines but its close. It makes a good sauce and is a good canner because of how easily it is peeled.
This post was edited by Kevinitis on Sun, Jan 6, 13 at 0:42
I grow Big Beef every year because it is consistent in its production and taste, you can't say that about some of those fussy heirloom ones (which I grow too). Don't let the name scare you, they don't get all that big, not like some of the beefsteak varieties anyway.
Not for me who has grown both hybrids and OP's, but since I have no idea which OP not heirlooms and which OP heirlooms you've grown it's impossible for me to comment more without input from you. ( smile)
And you're probably thinking that's a good thing, if you prefer F1's over OP's. LOL
I know you are the tomato expert, but take note of my zone...there are some heirloom or OP tomatoes that never mature during my growing season - and I've tried quite a few. The only hybrids I grow are Big Beef and Sungold...these are incredibly prolific.